Biomedical subjects

M Hossain

Publications and source records attributed to M Hossain.

At least 73 records · Page 4Linked to original sources

PubMed2000

Can plasma fructosamine substitute for glycated haemoglobin (HbA1c) estimation in the assessment of diabetic control?

The 'gold standard' marker of overall glycaemic control in diabetes mellitus is the level of glycated haemoglobin (HbA1c). It is, however, an expensive and technically difficult assay and is rarely appropriate to tropical laboratories. Plasma fructosamine measurement is cheaper and easier, though it reflects shorter-term glycaemia. We have measured both indices of control in a group of 154 diabetic patients. There was close correlation between the two measurements (r = 0.6506, P < 0.001), but many patients with abnormal HbA1c levels had normal fructosamine levels. This resulted in an assay sensitivity (compared with HbA1c as gold standard) of only 30%, though specificity was 98%. We conclude that fructosamine measurement cannot be regarded as a substitute for HbA1c determination.

Adolescent↗

PubMed1999

A clinical study on the removal of gingival melanin pigmentation with the CO(2) laser.

BACKGROUND AND OBJECTIVE: In a previous study, the possibility of removal of dog gingival melanin pigmentation with CO(2) laser therapy was reported. The present study was designed to investigate the effect of the CO(2) laser on human gingival pigmentation and evaluate the clinical outcome. STUDY DESIGN/MATERIALS AND METHODS: A CO(2) laser (output: 6-8 W, pulse duration: 0.2 seconds) was irradiated on the melanin pigmented gingival surface of 10 patients, aged 20-49 years. Follow-up clinical and histopathological evaluations were performed. RESULTS: The CO(2) laser was effective in removing melanin pigmentation in all patients. In the histopathological study, no pigmented-laden cells nor any inflammatory cell infiltration was observed following laser irradiation. No re-pigmentation was seen in any case in the first year. However, four of seven cases showed re-pigmentation at 24 months. The re-pigmentation was almost equal to the preoperative state. CONCLUSIONS: The CO(2) laser has proved to be another effective, safe, and easily applicable therapy for the removal of gingival melanin pigmentation.

Adult↗

PubMed1999

Effect of prenatal gamma irradiation during the late fetal period on the postnatal development of the mouse.

Pregnant Swiss albino mice were exposed to 0.3, 0.5, 1.0, or 1.5 Gy of gamma radiation on day 17 of gestation. Sham-exposed controls were examined for comparison. Exposed mice as well as controls were left to complete gestation and parturition. Pups were observed up to age 6 weeks; appearance of physiological markers (pinna detachment, eye opening, fur development, vaginal opening, and testes descent), postnatal mortality, body weight, body length, head length, head width, and tail length were recorded. A significant delay in fur development was observed at 0.3 Gy and in other physiological markers at doses above 0.3 Gy, while a significant increase in mortality and growth retardation occurred only at 1.0 and 1.5 Gy. Although congenital anomalies such as syndactyly and bent tail were observed at doses of 0.5-1.5 Gy, only syndactyly showed a statistically significant increase in frequency. A statistically significant lower body weight was observed during the first week of postnatal life, but body weights increased to normal levels by the second week in animals exposed to doses less than 1.0 Gy. At higher doses, low body weight persisted throughout the postnatal period. Head length and tail length showed a significant decrease from controls at 0.5-1.5 Gy, and the effect was evident from birth to age 6 weeks. But a similar effect on body length and head width was noticed only at 1.0 and 1.5 Gy. These studies indicate that even in the absence of any major morphological changes, normal development of physiological landmarks and postnatal growth can be impaired by fetal irradiation at 17 days p.c. (post coitus). Morphological changes appear to have a threshold between 0.3-0.5 Gy, while physiological marker effects may occur with a lower threshold.

Abnormalities, Radiation-Induced↗

PubMed1999

A case of an odontogenic cutaneous sinus tract.

CASE REPORT: A 22-year-old female presented with a draining sinus tract on her left cheek. The tooth responsible was examined clinicopathologically. On clinical examination, the mandibular left first molar tooth was restored with an amalgam filling. Radiographic examination revealed base or pulp capping material below the restoration and a radiolucent periapical lesion surrounding the distal root apex. Conservative non-surgical root canal treatment was performed; 10 months later, the sinus had healed completely and the periapical lesion had resolved. Histopathological examination of pulp tissue recovered during treatment revealed foreign bodies, made up of capping material and amalgam, associated with chronic inflammation. These findings suggested that chronic inflammation in the pulp tissue had resulted in a draining sinus tract.

Adult↗

PubMed1999

Validation of caregiver interviews to diagnose common causes of severe neonatal illness.

The objective of this study was to validate retrospective caregiver interviews for diagnosing major causes of severe neonatal illness and death. A convenience sample of 149 infants aged < 28 days with one or more suspected diagnoses of interest (low birthweight/severe malnutrition, preterm birth, birth asphyxia, birth trauma, neonatal tetanus, pneumonia, meningitis, septicaemia, diarrhoea, congenital malformation or injury) was taken from patients admitted to two hospitals in Dhaka, Bangladesh. Study paediatricians performed a standardised history and physical examination and ordered laboratory and radiographic tests according to study criteria. With a median interval of 64.5 days after death or hospital discharge, caregivers of 118 (79%) infants were interviewed about their child's illness. Using reference diagnoses based on predefined clinical and laboratory criteria, the sensitivity and specificity of particular combinations of signs (algorithms) reported by the caregivers were ascertained. Sufficient numbers of children with five reference standard diagnoses were studied to validate caregiver reports. Algorithms with sensitivity and specificity > 80% were identified for neonatal tetanus, low birthweight/severe malnutrition and preterm delivery. Algorithms with specificities > 80% for birth asphyxia and pneumonia had sensitivities < 70%, or alternatively had high sensitivity with lower specificity. In settings with limited access to medical care, retrospective caregiver interviews provide a valid means of diagnosing several of the most common causes of severe neonatal illness and death.

Algorithms↗

PubMed1999

Ablation depths and morphological changes in human enamel and dentin after Er:YAG laser irradiation with or without water mist.

OBJECTIVE: This investigation was performed quantitatively to determine the ranges of ablation and to evaluate the morphological changes in human enamel and dentin irradiated by Er:YAG laser with or without water mist. SUMMARY BACKGROUND DATA: Recently, several infrared lasers have been introduced in the dental clinic to remove carious dental hard tissues in anticipation of replacing the high-speed dental drill. Among them, the Er:YAG laser has shown the most promise for hard tissue ablation. METHODS: An Er:YAG laser was used to ablate human dental hard tissues using a pulse energy that ranged from 100 to 400 mJ at a frequency of 2 Hz for 5 seconds. Ablation rates with or without water mist at different pulse energies were measured, and the morphological changes on enamel and dentin were also investigated by stereomicroscopy and scanning electron microscopy (SEM). RESULTS: The relationship between ablation depths and energies was almost linear at both enamel and dentin samples. The irradiation with water mist reduced the ablation depths, but only minimally, when compared to those irradiated without water mist. Morphological findings by SEM indicated that Er:YAG laser irradiation with water mist could produce the cavities without signs of thermal damage to the surrounding enamel and dentin. CONCLUSIONS: The results of this study suggest that addition of a fine water mist directed at the ablation sites does not greatly decrease the ablation, and does not cause any carbonization and melting in the surrounding dental hard tissues.

Dental Enamel↗

PubMed1999

Morphological changes of rat mandibular bone with ArF excimer laser in vivo.

OBJECTIVE: The purpose of this study was to investigate the morphological changes of bone tissue by ArF excimer laser irradiation in vivo. SUMMARY BACKGROUND DATA: Recently, it has been demonstrated that soft and hard tissues can be removed by excimer laser irradiation with little thermal damage. METHODS: ArF excimer laser was irradiated on the surface of the rat mandibular bone using the following parameters: wavelength; 193 nm; output: 0.12 W; pulse repetition rate: 10 Hz; spot size: 1.0 x 4.0 mm; irradiation time: 90 and 120 seconds. The ablation depth was measured at 90 and 120 seconds. Furthermore, the irradiated surface was examined histologically using scanning electron microscopy (SEM). RESULTS: The relationship between ablation depth and irradiation time was almost linear. Macroscopically, the ArF excimer laser beam produced a defect with clean-cut margins without carbonization in the mandibular bone. Histologically, there was minimal evidence of thermal damage to the surrounding tissue. The bottom of the defect revealed a sawtooth appearance. In SEM observation, mosaic structures corresponded to the sawtooth structures observed with light microscopy. CONCLUSIONS: These findings suggest that it is possible to remove bone tissue using ArF excimer laser irradiation without thermal damage. The effectiveness of this laser can be attributed to the photoablation of the bone tissue.

Animals↗

PubMed1999

Effects of Er,Cr:YSGG laser irradiation in human enamel and dentin: ablation and morphological studies.

OBJECTIVE: This investigation was performed to determine quantitatively the ranges of ablation and to evaluate the morphological changes in human enamel and dentin irradiated by Er,Cr:YSGG laser with or without water spray. SUMMARY BACKGROUND DATA: Recently, Er,Cr:YSGG laser has been introduced in dental clinics to remove carious dental hard tissues in anticipation of replacing the high-speed dental drill. METHODS: A total of 40 extracted human teeth were used in this study. An Er,Cr:YSGG laser was used to ablate human dental hard tissues with the output powers of 3 to 6 W. Ablation extent with or without water spray at different output powers was measured, and the morphological changes on enamel and dentin were also investigated by stereoscopy and scanning electron microscopy (SEM). RESULTS: The irradiation with water spray significantly (p < 0.001) increased the ablation depths compared to those irradiated without water mist. Morphological findings by SEM indicated that when irradiated without water spray, carbonization with brown or dark color was recognized in enamel or dentin, respectively. In addition, cavities with a molten lava-like appearance were produced and an irregular structure with many microholes was observed in dentin. CONCLUSIONS: These results suggest that during the Er,Cr:YSGG laser irradiation, water spray directed at the ablation sites increases the ablation depths and water plays an important role as an initiator of the ablation of dental hard tissues.

Dental Enamel↗

PubMed1999

A study on the morphological changes of the rat mandibular bone with TEA CO2 laser.

OBJECTIVE: The purpose of this study was to investigate the morphological changes of the bone structure induced by transversely excited, atmospheric TEA pressure CO2 laser irradiation. Moreover, the healing process at 3 weeks was also observed. SUMMARY BACKGROUND DATA: It has been demonstrated that dental hard tissue can be removed by a long pulse of TEA CO2 laser irradiation with minimal thermal damage. However, there are few studies on the morphological changes of the TEA CO2 laser on bone tissue. METHODS: The TEA CO2 laser was irradiated on the surface of the rat mandibular bone under the following irradiation conditions: wavelength, 10.6 microns; output, 95 mJ/pulse; pulse repetition rate, 1 Hz; irradiation time, 7.5 microseconds/shot; spot size, 0.8 x 1.5 mm; energy density, 7.9 J/cm2. Histological and scanning electron microscopic examinations were performed. RESULTS: In the stereoscopic examination, a defect with clean-cut margins was produced. In the light microscopic examination, a basophilic line at the bottom of the defect was noted. Examining the defect with SEM, a smear-like appearance and cone structures were found. In the histological examination, a healing process by formation of new bones at the junction site was recognized. CONCLUSIONS: These findings suggest that it is possible to remove bone tissues by TEA CO2 laser irradiation. However, a particle-like structure associated with a basophilic line and melted surface indicated that some thermal damage was produced during the laser irradiation.

Animals↗

PubMed1999

Acquired acid resistance of dental hard tissues by CO2 laser irradiation.

OBJECTIVE: This investigation was performed to evaluate the effect of CO2 laser irradiation on the acquired acid resistance of dental hard tissues to artificial caries-like formation and the ultrastructure of lased areas was morphologically investigated in vitro. SUMMARY BACKGROUND DATA: In recent years, many studies have been carried out to evaluate the effect of the CO2 laser on the enhanced resistance to artificial caries formation of enamel. However, a limited number of papers concerning its effect on dentin have been published. METHODS: A CO2 laser of 10.6 microns wavelength was used to irradiate human enamel and dentin samples from 20 extracted human molar teeth, and samples were subjected to 2 microliters of 0.1 M lactic acid solution (pH 4.8) for 24 h at 36 degrees C. The parts per million (ppm) of calcium ion (Ca2+) dissolved in each solution was determined by atomic absorption spectrophotometry and the morphological changes were investigated by scanning electron microscopy (SEM). RESULTS: The lowest mean Ca2+ ppm was recorded in the samples irradiated at 3 W, followed by 2 W, 1 W, and unlased samples. SEM observation showed that the lased areas were melting with solidification of the smear layer. Even after acid demineralization, the lased surfaces were almost unchanged. CONCLUSIONS: The results of this study suggested that CO2 laser irradiation could sufficiently melt and solidify the enamel and dentin surfaces and thus enhance resistance to artificial caries-like formation.

Acids↗

PubMed1999

Effects of copper vapor laser irradiation in human enamel and dentin: ablation and morphological studies.

OBJECTIVE: This investigation was performed to determine the ranges of ablation quantitatively and to evaluate the morphological changes in human enamel and dentine irradiated by a green copper vapor laser. SUMMARY BACKGROUND DATA: Recently, green copper vapor laser (CVL), which is said to have characteristics similar to the argon laser has been introduced in dentistry. METHODS: Extracted noncarious human teeth were used in this study. A CVL was used to ablate human dental hard tissues with the output powers of 2.0 W. Ablation extent without water spray using red or black ink was measured, and the morphological changes on enamel and dentin were also investigated by stereoscopy and scanning electron microscopy (SEM). RESULTS: In the samples, irradiated by a CVL after painting red ink on the surface, the ablation depth was increased more than that of irradiation after painting with black ink. Morphological findings by SEM indicated that when irradiated with red ink, brown carbonization was recognized on enamel and dentin surfaces. In addition, cavities with a molten lava-like appearance were produced and an irregular structure with many microholes was observed in the enamel and dentin. Alternatively, a shallow cavity with little carbonization was produced with black ink. CONCLUSIONS: Removal of dental hard tissues appears to be possible using the CVL. However, further studies should be performed on the selection of radiation conditions that achieve the desired ablation with minimal side effects.

Copper↗

PubMed1999

Nursing home characteristics and the development of pressure sores and disruptive behaviour.

OBJECTIVE: To determine how nursing home characteristics affect pressure sores and disruptive behaviour. METHOD: Residents (n = 5518, aged > or =60 years) were selected from 70 nursing homes in the National Health Care chain. Homes were classified as high- or low-risk based on incidence tertiles of pressure sores or disruptive behaviour (1989-90). Point-prevalence and cumulative incidence of pressure sores and disruptive behaviour were examined along with other functional and service variables. RESULTS: The overall incidence of pressure sores was 11.4% and the relative risk was 4.3 times greater in high- than low-risk homes; for disruptive behaviour, the incidence was 27% and the relative risk was 7.1 times greater in the high-risk group. At baseline, fewer subjects in homes with a high risk of pressure sores were white or in restraints, but more had received physician visits monthly and had had problems with transfers and eating. High-risk homes also had fewer beds and used less non-licensed nursing staff time. At follow-up (1987-90), 52% of homes in the low-risk group and 35% of those in the high-risk group had maintained their risk status; low-risk homes were more likely to have rehabilitation and maintenance activities. Having multiple clinical risk factors was associated with more pressure sores in high- (but not low-) risk homes, suggesting a care-burden threshold. By logistic regression, the best predictor of pressure sores was a home's prior (1987-88) incidence status. Interestingly, 67% of homes with a high risk of pressure sores were also high-risk for disruptive behaviour, while only 27% of homes with a low risk of pressure sores were high-risk for disruptive behaviour. A threshold effect was also observed between multiple risk factors and behaviour. More homes with a high risk of disruptive behaviour (68%) remained at risk over 4 years, and the best predictor of outcome was a home's previous morbidity level. CONCLUSION: Nursing-home characteristics may have a greater impact than clinical factors on pressure sores and disruptive behaviour in long-stay, institutionalized elders.

Aged↗

PubMed1999

Relation of surgical volume to outcome in eight common operations: results from the VA National Surgical Quality Improvement Program.

OBJECTIVE: To examine, in the Veterans Health Administration (VHA), the relation between surgical volume and outcome in eight commonly performed operations of intermediate complexity. SUMMARY BACKGROUND DATA: In multihospital health care systems such as VHA, consideration is often given to closing low-volume surgical services, with the assumption that better surgical outcomes are achieved in hospitals with larger surgical volumes. Literature data to support this assumption in intermediate-complexity operations are either limited or controversial. METHODS: The VHA National Surgical Quality Improvement Program data on nonruptured abdominal aortic aneurysmectomy, vascular infrainguinal reconstruction, carotid endarterectomy (CEA), lung lobectomy/pneumonectomy, open and laparoscopic cholecystectomy, partial colectomy, and total hip arthroplasty were used. Pearson correlation, analysis of variance, mixed effects hierarchical logistic regression, and automatic interaction detection analysis were used to assess the association of annual procedure/specialty volume with risk-adjusted 30-day death (and stroke in CEA). RESULTS: Eight major surgical procedures (68,631 operations) were analyzed. No statistically significant associations between procedure or specialty volume and 30-day mortality rate (or 30-day stroke rate in CEA) were found. CONCLUSIONS: In VHA hospitals, the procedure and surgical specialty volume in eight prevalent operations of intermediate complexity are not associated with risk-adjusted 30-day mortality rate from these operations, or with the risk-adjusted 30-day stroke rate from CEA. Volume of surgery in these operations should not be used as a surrogate for quality of surgical care.

Adolescent↗

PubMed1999

Blood pressure behavior in the nursing home: implications for diagnosis and treatment of hypertension.

OBJECTIVES: To determine patterns of elevated blood pressure (BP) behavior, their clinical correlates, and the relationship to diagnosis and management of hypertension. DESIGN: A cross-sectional, prevalence survey. SETTING: Forty-five nursing homes owned or managed by a large national chain. PARTICIPANTS: A total of 857 older residents (mean age = 84 years). MEASUREMENTS: Supine and standing (1 and 3 minutes) BP and heart rate, taken four times in one day (before and after breakfast, and before and after lunch) by trained nurses using a random zero sphygmomanometer; medication profile; active medical diagnoses; functional status; sociodemographics. RESULTS: The prevalence of a single, elevated, supine systolic pressure (> or = 160 mm Hg) was 14.3%, and of two to four elevated measures was 14.9%. The pre-breakfast reading was consistently the highest, and mean systolic pressures decreased after breakfast. Compared with those not treated, older residents taking antihypertensive medications had higher systolic pressures at all times and showed the same pattern of decline after breakfast. Isolated diastolic hypertension was uncommon (0.9%). Cardiovascular disease, orthostatic hypotension, diabetes, and use of angiotensin converting enzyme inhibitors or calcium channel blockers were more prevalent among older residents who had elevated pressures on multiple occasions (P < .03). Successful antihypertensive treatment was associated with a lower prevalence of orthostatic hypotension. Diuretic use was more likely to be associated with blood pressure control. CONCLUSION: The diagnosis of hypertension in frail older people would benefit from multiple, within-day measures, including postural BP, taken before and after meals. Diuretic use alone, or in conjunction with ACE inhibitors or calcium channel blockers, was more likely to be associated with normalized blood pressures.

Aged↗

PubMed1999

Population pharmacokinetics. A regulatory perspective.

The application of population approaches to drug development is recommended in several US Food and Drug Administration (FDA) guidance documents. Population pharmacokinetic (and pharmacodynamic) techniques enable identification of the sources of inter- and intra-individual variability that impinge upon drug safety and efficacy. This article briefly discusses the 2-stage approach to the estimation of population pharmacokinetic parameters, which requires serial multiple measurements on each participant, and comprehensively reviews the nonlinear mixed-effects modelling approach, which can be applied in situations where extensive sampling is not done on all or any of the participants. Certain preliminary information, such as the compartment model used in describing the pharmacokinetics of the drug, is required for a population pharmacokinetic study. The practical design considerations of the location of sampling times, number of samples/participants and the need to sample an individual more than once should be borne in mind. Simulation may be useful for choosing the study design that will best meet study objectives. The objectives of the population pharmacokinetic study can be secondary to the objectives of the primary clinical study (in which case an add-on population pharmacokinetic protocol may be needed) or primary (when a stand-alone protocol is required). Having protocols for population pharmacokinetic studies is an integral part of 'good pharmacometric practice'. Real-time data assembly and analysis permit an ongoing evaluation of site compliance with the study protocol and provide the opportunity to correct violations of study procedures. Adequate policies and procedures should be in place for study blind maintenance. Real-time data assembly creates the opportunity for detecting and correcting errors in concentration-time data, drug administration history and covariate data. Population pharmacokinetic analyses may be undertaken in 3 interwoven steps: exploratory data analysis, model development and model validation (i.e. predictive performance). Documentation for regulatory purposes should include a complete inventory of key runs in the analyses undertaken (with flow diagrams if possible), accompanied by articulation of objectives, assumptions and hypotheses. Use of diagnostic analyses of goodness of fit as evidence of reliability of results is advised. Finally, the use of stability testing or model validation may be warranted to support label claims. The opinions expressed in this article were revised by incorporating comments from various sources and published by the FDA as 'Guidance for Industry: Population Pharmacokinetics' (see the FDA home page http:/(/)www.fda.gov for further information).

Data Interpretation, Statistical↗

PubMed1999

A natural response to drug misuse problems: a review of drug-user treatment services of Bangladesh.

This paper reviews and describes the natural processes through which the people of a Third World country, Bangladesh, have been trying to provide treatment to drug misusers. As the demand for medical help increases, different organizations develop to cater to the needs. Bangladesh has followed the age-old ashram model and the contemporary medical hospital model to provide services to its addicts. In reality the drug misuse treatment providers are still evolving through different learning stages about the biopsychosocial manifestations of addiction. According to the authors, the stages of learning can be divided into three phases: 1) the early period of confusion and enthusiasm, 2) the period of truism, and 3) the period of pragmatism. The people who have gained experience in running treatment centers in the last decade need to form alliances to share their experiences in order to develop rational models for drug treatment programs in Bangladesh. It is also important that they develop methods to monitor providers' activities and to protect clients' safety and interests.

Attitude of Health Personnel↗

PubMed1999

Characterization of a phase 1-d epitope on Salmonella typhi flagellin and its role in the serodiagnosis of typhoid fever.

A monoclonal antibody (MAb) directed against Salmonella typhi 52 kDa flagellin protein has been previously produced by our group. In this study, we have demonstrated that the epitope specific to the MAb is unique to phase 1-d. To map the epitope, plasmids encoding different regions of S. typhi flagellin gene were constructed. Analysis of protein produced from each recombinant plasmid indicated that the epitope specific to the MAb resided within amino acids 171-303 (region IV) of S. typhi flagellin protein. The recombinant region IV flagellin was used to develop an ELISA for the detection of IgM antibody to S. typhi in serum. In the hemoculture-positive typhoid group, the developed ELISA was positive in 77 of 92 cases. In patients with non-typhoidal Salmonella, gram-positive and gram-negative bacteria or dengue virus, the ELISA was negative in all 78 cases. Two from 116 healthy control subjects had positive reactions with the assay. The calculated sensitivity, specificity, positive and negative predictive values of the test were 83.7%, 99.0%, 97.5% and 92.8%, respectively. With such high validity together with the requirement of only a single serum specimen and one day for performing the test, the developed ELISA should become a valuable diagnostic test for typhoid fever.

Antibodies, Monoclonal↗

PubMed1998

Effect of gamma radiation on the foetal haemopoietic system in the mouse.

PURPOSE: To study the effect of gamma irradiation, in the late foetal period, on the haemopoietic progenitor cells of the mouse foetus. MATERIALS AND METHODS: Pregnant Swiss mice were exposed to 0.1 to 1.5 Gy of Cobalt-60 gamma radiation on the 17th day of gestation. At 24h (18 day p.c.) and 72 h (20 day p.c.) after exposure the weights of foetal liver and spleen and their mean cellularity were determined. Chromosomal aberrations and micronuclei (MN) were studied at 24 h. Haemopoietic progenitor cell survival at 24 and 72 h post-irradiation was studied by exogenous spleen colony assay. RESULTS: Irradiation caused significant reduction in the weights of foetal liver and spleen, which was more pronounced at 72 h post-irradiation. The mean cellularity as well as the CFU-S8 and CFU-S12 of liver and spleen showed a radiation dose-dependent decrease, but the spleen showed a higher sensitivity than liver to doses below 1.0 Gy. Chromosomal damage in liver increased linearly with dose, while in spleen the increase was linear-quadratic. CONCLUSIONS: The results demonstrate the damaging effect of low doses of gamma radiation on the late foetal haemopoietic progenitor cells of the mouse. Induction of cytogenetic damage appears to be a no-threshold effect in the dose range used.

Animals↗