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Biomedical subjects

Z Khan

Publications and source records attributed to Z Khan.

At least 55 records · Page 3Linked to original sources
PubMed1999

Effect of congestive heart failure on in vivo canine aortic elastic properties.

OBJECTIVES: The aim of this study was to characterize fully in vivo aortic compliance over a wide range of passive distending pressures, and to study pharmacologically induced alterations in compliance using an intravascular ultrasound-based technique in the canine model of heart failure. BACKGROUND: Altered aortic compliance may influence considerably the function of the failing heart. Although some studies demonstrate that patients with heart failure have decreased aortic compliance, data from other studies are conflicting. METHODS: Aortic pressures and dimensions in seven dogs were determined both before and after pacing-induced congestive heart failure (CHF) using simultaneous micromanometer and intravascular ultrasound transducers. Decreases in aortic pressure were produced at baseline and after nitroprusside and dobutamine infusions. Inner and outer aortic circumferences were drawn at the lumen-intimal and media-adventitial borders. RESULTS: Aortic pressure-dimension (chamber) stiffness constants were greater after heart failure was produced (10.0+/-1.5 vs. 6.7+/-1.5, p < 0.05), but stress-strain stiffness (material) constants were similar (11.4+/-1.8 vs. 11.3+/-1.0, p=NS). Equivasodilating doses of nitroprusside and 10 microg/kg/min dobutamine decreased pressure-dimension stiffness constants after pacing-induced heart failure but not beforehand. The aortic wall thickness to diameter ratio was significantly greater in CHF than in the control condition (0.30+/-0.08 vs. 0.16+/-0.03, p < 0.01). CONCLUSIONS: Aortic compliance is decreased in this model of CHF, and this change is attributable primarily to vessel geometry rather than material properties. Equivasodilating doses of nitroprusside and equivalent doses of dobutamine increase aortic chamber compliance in dogs with CHF, but not in normal dogs. These data suggest that the beneficial effects of nitroprusside and dobutamine in CHF occur in part from improvement in aortic compliance.

Animals↗
PubMed1999

Comparison of intra-articular fentanyl and intra-articular bupivacaine for post-operative pain relief after knee arthroscopy.

A randomized double-blinded study consisting of 107 patients was conducted to compare the effect on post-operative pain relief of intra-articular fentanyl and intra-articular bupivacaine after knee arthroscopy. The results showed that intra-articular bupivacaine produced superior analgesia in the immediate post-operative period. At 2 h post-operatively, the intra-articular bupivacaine group had a mean pain score of 2.0 (standard deviation 2.1, P < 0.05) compared with the intra-articular fentanyl group which had a mean pain score of 3.2 (standard deviation 2.3, P < 0.05). After 2 h post-operatively, intra-articular bupivacaine and intra-articular fentanyl had a similar effect on pain scores. The mean pain score 18 h post-operatively was 2.7 for the intra-articular bupivacaine group (standard deviation 2.2, P value 0.6) compared with the intra-articular fentanyl group which had a mean pain score of 2.8 (standard deviation 1.9, P value 0.6).

Adult↗
PubMed1999

Prospective randomized comparison of tropisetron with and without dexamethasone against high-dose metoclopramide in prophylaxis of acute and delayed cisplatin-induced nausea and vomiting.

Several studies have confirmed the efficacy of high-dose metoclopramide and, more recently, serotonin antagonists, with and without dexamethasone, in the prophylaxis of cisplatin-induced nausea and vomiting. Most of these trials have been reported from Western countries. There is little or no information about the efficacy and tolerability of these agents in ethnic groups in other countries. Furthermore, many patients in the developing countries cannot afford serotonin antagonists. The result is a critical need to evaluate these agents and justify their increasingly common use. The authors performed a prospective randomized trial to compare the efficacy and tolerability of tropisetron with and without dexamethasone against high-dose metoclopramide cocktail in patients receiving a uniform dose of cisplatin (100 mg/m2). Metoclopramide 2 mg/kg was combined with clemastine, dexamethasone, and lorazepam. These drugs were initially repeated at short intervals and subsequently given in the oral form for the next 5 days. Tropisetron 5 mg was administered intravenously 15 minutes immediately before cisplatin therapy and followed up with oral therapy for 5 days. The third group received the same doses of tropisetron along with dexamethasone before cisplatin and twice daily thereafter. The authors randomized 301 episodes. The patient characteristics were well balanced between the three groups. Acute nausea and vomiting were completely prevented in almost two thirds of patients receiving metoclopramide and tropisetron plus dexamethasone. These results are significantly superior to those of tropisetron alone (p < 0.01). Similarly, delayed nausea and vomiting were significantly better controlled with metoclopramdie cocktail and tropisetron plus dexamethasone than with tropisetron alone. Side effects were generally mild; however, they were more frequent with metoclopramide. The authors conclude that metoclopramide-based combination antiemetic therapy continues to be a cheaper alternative to serotonin antagonists and equally effective. Metoclopramide-based therapy, however, is more labor intensive, and issues related to administrative errors, side effects, and compliance gain increasing importance. The identification of persons at a higher risk for metoclopramide-induced side effects may help minimize the unacceptable consequences of therapy.

Acute Disease↗
PubMed1999

Laparoscopic cholecystectomy: experience with 303 patients over the initial four years.

A total of 303 patients underwent attempted laparoscopic cholecystectomy (LC) over a four-year period by two consultant surgeons or a senior trainee under their supervision. The procedure was completed in 291 with a conversion rate to open cholecystectomy of 3.9% and a median postoperative length of stay of two days, range zero to nine days. In eighteen patients the indication for LC was failure of symptoms to settle, two of whom required conversion (11.1%). Diathermy dissection was avoided in Calot's triangle and dissection started at the junction of Hartmann's pouch and cystic duct with full mobilisation of this area prior to clip application. Pre-operative endoscopic retrograde cholangiopancreatography ERCP was performed in patients suspected of having common bile duct stones without routine intra-operative cholangiography. There was one death in this series (0.3%) and an overall complication rate of 6.3 %. There was no incidence of either bile duct injury or leak. LC can be performed with a low complication rate with attention to careful dissection technique in the region of Calot's triangle.

Adolescent↗
PubMed1998

Cattle plague in Shangri-La: observations on a severe outbreak of rinderpest in northern Pakistan 1994-1995.

Between April 1994 and November 1995 the most severe epidemic of rinderpest reported in the world for over a decade affected domestic livestock in the Northern Areas of Pakistan. As many as 40,000 cattle and yaks died, more by some estimates, and mortality rates may have exceeded 80 per cent in these species in several villages. This report describes some of the clinicopathological and epidemiological features peculiar to the outbreak, including laboratory-confirmed rinderpest in a goat, and the difficulties encountered before the disease was eradicated. It also describes the human costs and emphasises the need to accelerate the global eradication of this most eradicable disease.

Agriculture↗
PubMed1997

Construction of a custom-shaded interim denture using visible-light-cured resin.

A patient treatment is presented to demonstrate a technique using visible-light-cured (VLC) resin to create a characterized denture base for an interim denture. This indication for characterization is routinely seen with African-Americans with dark-pigmented gingiva. Using a combination of blue VLC tray resin and pink VLC denture base resin, the mixture achieves a darker-colored denture base. This technique was used for the fabrication of an interim denture for a patient who required an immediate interim denture. The prosthesis was worn during the healing phase and allowed the patient to function while the definitive prosthesis was being fabricated.

Adult↗
PubMed1997

A baseline study of tobacco use among the staff of Aligarh Muslim University, Aligarh, India.

A cross-sectional study of 2,439 university employees and research scholars was carried out using the questionnaire method. The objective was to assess the prevalence and type of tobacco usage and to collect background data for planning health education programmes. The overall prevalence of tobacco usage was 51.5% among males and 30.3% among females. There were no female smokers, the preferred habit of tobacco usage among women being chewing. The prevalence of smoking among non-teaching staff members was significantly higher. Among females, the prevalence of tobacco chewers was higher in non-teaching staff members. Tobacco usage (both smoking and usage of other forms) rose with age. However, even at 20-30 years of age 25.4% of males were addicted to smoking. A majority of 60.6% had smoked for more than 10 years. Among the staff members (both teaching and non-teaching) the reason for smoking was either to relax or because of addiction, whereas the research scholars smoked to improve their image or for enjoyment/pleasure. The reasons given by users of other forms of tobacco were boredom, to pass the time or for no reason at all. Among non-users, the majority were aware of the harmful effects of smoking. Family pressure and traditions were also important reasons for not smoking. The study provides a clear picture of tobacco usage within the University.

Adult↗
PubMed1996

Long-term benefits of aggressive treatment for primary colorectal cancer.

The long-term follow up of 128 colorectal cancer patients is reported. Seventy-nine percent (101/128) of the patients had curative resections: 70 patients had radical lymphadenectomies with wide removal of tumor-adjacent nodes, and 31 patients had standard resections. The 5-year overall survival rates for Dukes' stage B and C patients and for all rectosigmoid cancer patients significantly favored radical resection (60% vs. 38%, 57% vs. 29%, respectively, P < 0.05). Tumor-free survival rates were also higher after radical lymphadenectomy but did not reach statistical significance. Eleven percent (14/128) of the patients required multiorgan resections, and/or preoperative radiation to render fixed cancers resectable, and these patients had a 10-year tumor-free survival rate of 45%, compared to zero % 5-year survival for the 27 patients who underwent palliative procedures (P < 0.01). These results confirm that many colorectal cancer patients will be cured with aggressive treatment and they support the need for a controlled trial for evaluation of lymphadenectomy for this disease.

Adult↗
PubMed1996

Role of weaning in the nutritional status of infant--a longitudinal study in the rural area of Aligarh.

Influences of weaning practices on nutritional status were studied in a cohort of 200 infants over a period of one year in the rural area of Aligarh. Weaning was late in most of the infants under study. The nutritional status of infants up to 6 months was significantly better than that of infants more than 6 months of age. Most of them used the family-type food as weaning food.

Developing Countries↗
PubMed1995

Simultaneous assessment of cell kinetics and programmed cell death in bone marrow biopsies of myelodysplastics reveals extensive apoptosis as the probable basis for ineffective hematopoiesis.

Despite hypercellular bone marrows (BM), peripheral cytopenias are the rule in patients with myelodysplastic syndromes (MDS). This study examined the roles played by cell birth and cell death rates in generating this paradox. Cell kinetics from BM biopsies of 35 MDS patients were measured using intravenous infusions of either iododeoxyuridine or bromodeoxyuridine, or both. Degree of apoptosis or programmed cell death (PCD) was estimated using in situ end-labeling of DNA directly from BM biopsies, which were simultaneously double-labeled from proliferation/PCD. MDS were found to be highly proliferative disorders with large numbers of myeloid, erythroid, and megakaryocytic cells synthesizing DNA. Median cycling time (Tc) of myeloblasts was more rapid than that of patients with acute myeloid leukemia (44.1 hr vs. 56.0 hr). Interestingly, most marrow cells of all three lineages in 32 of 34 evaluable cases were undergoing PCD. In 19 of 32 patients, greater than 75% cells were apoptotic. Surprisingly, large numbers of S-phase cells were found to be simultaneously undergoing PCD, as were stromal cells of the BM microenvironment. We conclude that the extensive apoptosis in hematopoietic cells effectively cancels the high birth rate resulting in ineffective hematopoiesis and accounting for deficient bone marrow function.

Acute Disease↗
PubMed1995

Fate of the upper urinary tract in multiple sclerosis.

Urologic problems are a major source of morbidity for patients with multiple sclerosis (MS). Fifty-four to 78% of patients experience bladder symptoms which are due to spinal lesions interrupting neural pathways that control micturition. MS patients could have upper or lower motor neuron lesion type bladders. Both obstructive and irritative symptoms may be present. Although lower urinary tract dysfunction has been well described in MS, few studies have investigated the fate of the upper urinary tract. Thirty-two patients with MS were referred for urodynamic evaluation. Twenty-six of the 32 patients had upper urinary tract studies performed. Only 1 of the 26 patients had evidence of upper urinary tract deterioration. It is our impression that upper tract deterioration occurs infrequently in these patients. We discuss clinical clues that may predict deterioration.

Adult↗
PubMed1995

Anatomic site evaluation of edentulous maxillae for dental implant placement.

PURPOSE: This study evaluated 17 edentulous cadavers for bone quantity and quality of the alveolar process of the maxilla for the purpose of dental implant placement. MATERIALS AND METHODS: The maxillary arch was divided into four anatomically defined regions for measurements of bone quantity. Bone quality was assessed histologically and described by trabecular bone patterns and tissue composition. RESULTS: Average bone height with a minimum thickness of 4 mm was as follows: region 1, 12.1 +/- 4.9 mm; region 2, 14.1 +/- 7.2 mm; region 3, 6.1 +/- 2.8 mm; and region 4, 8.5 +/- 2.2 mm. Histological evaluation showed increased trabeculation and thicker cortex in the maxillary anterior area, regions 1 and 2. Region 3, the floor of the maxillary sinus area, had the least amount of bone; however, the quality of bone was superior to that of region 4, the maxillary tuberosity area. Trabecular distance or marrow spaces ranged from 40 microns to 2 mm with larger spaces associated with the posterior maxilla. CONCLUSIONS: Maxillary tuberosity is the least desirable site for the placement of implants in the maxilla. The area corresponding to the first and second molars had the least bone thickness. All measures of bone preservation need to be considered, especially in this area.

Aged↗
PubMed1994

Molecular heterogeneity of the type I GABAA/benzodiazepine receptor complex.

We have investigated the presence of alpha 1, gamma 2 and beta 2-3 subunits as part of the type I (high affinity for [3H]zolpidem) GABAA/benzodiazepine receptor from rat cerebral cortex. Three subunit specific antibodies have been used (anti-alpha 1, to the C-terminal of rat alpha 1 subunit; anti-gamma 2, to the large intracellular loop of the gamma 2 subunit short form and the monoclonal 62-3G1, specific to beta 2-3 subunits) in immunoprecipitation experiments of the [3H]zolpidem binding activity or the 51,000 Da [3H]Ro 15-4513 photoaffinity labeled peptide (P51). The results indicated that alpha 1 subunit was present in the whole population (90%) of the GABAA/benzodiazepine receptors with high affinity for [3H]zolpidem. We cannot exclude the presence of other alpha subunits co-localized with alpha 1. On the one hand, 70-75% of type I GABAA/benzodiazepine receptor from rat cortex have co-existing alpha 1, beta 2-3 and gamma 2 subunits. We call this type Ia. On the other hand, 20-25% of the type I GABAA/benzodiazepine receptor complex should be constructed by the association of alpha 1 with subunits other than beta 2-3 and gamma 2. We call this type Ib. The identity of these subunits is currently unknown.

Animals↗
PubMed1994

Modified bar superstructure for an implant-retained orbital prosthesis.

The success of a bar superstructure for an orbital prosthesis may be compromised by the placement and angulation of implants. The following technique describes a modification to a bar superstructure that provided the advantages of convenience, security, and consistent positioning even though one implant was lost and the angulation of implants limited accuracy.

Eye, Artificial↗