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Biomedical subjects

A Zafar

Publications and source records attributed to A Zafar.

At least 37 records · Page 2Linked to original sources
PubMed1996

The detection of verocytotoxins in bacterial cultures from human diarrhoeal samples with monoclonal antibody-based ELISAs.

Bacterial cultures from 1801 human diarrhoeal faecal specimens were examined for verocytotoxins I and II by monoclonal antibody-based sandwich ELISAs. Of the 68 ELISA-positive cultures selected from initial screening, 32 were positive by ELISA on repeat or from freshly grown cultures. ELISA-positive pure cultures were obtained from 13 of these, of which seven were confirmed as verocytotoxin positive by cytotoxicity assay. These seven strains were typed as O26 (5) and O146 (2). The six false positive results were from isolates of Enterobacter sp. (1), Citrobacter Freundii (1) and Escherichia coli (4), one each of types O1, O18ac and O98 and an untypable strain. Despite the occurrence of false positive reactions, sandwich ELISA was a useful method for the rapid screening of samples, and detected verocytotoxin-positive E. coli strains, other than O157, from patients with clinical conditions in which they could be implicated.

Adult↗
PubMed1996

Ruptured aneurysm of the sinus of Valsalva.

The objective of the present study was to assess the value of imaging techniques in the diagnosis of ruptured aneurysm of sinus of Valsalva (RASV). 38 patients were included in the study. 30 were male and 8 female. Their age ranged from 7 to 55 years (mean 25.8 years). Echocardiographic and doppler studies were done in all cases and 20 patients underwent catheterization and angiography. Two patients were asymptomatic, 20 (53%) had acute onset of symptoms and in the remaining 16 (42%) patients symptoms developed gradually. Twenty two (58%) patients were in NYHA functional class III or IV when first seen. Predominant symptoms were dyspnea (79%), palpitation (55%) and chest pain (52%). A continuous machinery murmur was detected in all the patients with associated thrill in 34 patients. Right coronary sinus (RCS) was the most common sinus involved (89%) followed by the noncoronary sinus (NCS) which was involved in 11% of patients. None of the patients in our series had aneurysm of the left coronary sinus. Twenty eight of the 34 RCS aneurysms ruptured into the right ventricular outflow tract (RVOT), 4 into right ventricular cavity (RVC), one into right atrium (RA) and one dissected into the ventricular septum and subsequently ruptured into the left ventricle. Of the 4 NCS aneurysms, 2 ruptured into RVC, one into RA and one into both the RA and RVC. Associated ventricular septal defect (VSD) was found in 10 (26%) patients and all of these patients had RCS aneurysm that ruptured into the RVOT. Aortic regurgitation (AR) was detected in 16 (42%) cases. Discrete subaortic stenosis was detected in one patient who also had associated VSD and AR. Vegetation of the aortic valve was detected in one patient who had RCS aneurysm. Twelve patients (11 male and one female) underwent surgical correction, 10 with and 2 without prior catheterization. Localization of the involved sinus, site of rupture and associated cardiac lesions by echocardiography and doppler study were found accurate at surgery and/or angiography in 22 cases of our series. Imaging techniques, thus appeared to be reliable tools for the diagnosis of RASV.

Adolescent↗
PubMed1996

Conduction disturbances in acute myocardial infarction: incidence, site-wise relationship and the influence on in-hospital prognosis.

The study was designed to assess the incidence of conduction disturbances, the relationship of the site of infarction with the type of conduction disturbances and the influence of conduction disturbances on the in-hospital prognosis. One hundred consecutive patients (M:F = 89:11) with a age range of 35-60 years with the history of first attack of acute myocardial infarction were included in the study. There were 45 anterior, 43 inferior and 12 combined anterior and inferior myocardial infarction patients. 44 of the patients had some type of conduction disturbances (Group A) and 56 had none (Group B). Inferior myocardial infarction patients showed higher incidence of conduction disturbances than anterior myocardial infarction (56.8% and 31.8% respectively) (Odd's ratio 2.98, 95% ci 1.14 to 7.9). Conduction disturbances were mostly (92%) atrio-ventricular in inferior myocardial infarction and mostly (72%) intraventricular in anterior myocardial infarction. Of the 13 cases of complete atrioventricular block, 8 had inferior, 2 anterior and 3 combined anterior and inferior infarction. In inferior infarction, complete atrioventricular block developed gradually through 1 degree and 2 degrees atrioventricular block but in the anterior infarction it developed suddenly. Patients with conduction disturbances developed more complications (84%) than those without conduction disturbances (54%). Mortality rate was higher in Group A (25%) than in Group B (3.6%) (Odd's ratio 9.0, 95% ci 1.76 to 86.73) with a overall rate of 13%. Mortality rate was higher in anterior myocardial infarction (50%) than in inferior myocardial infarction (25%) when complicated by complete atrioventricular block. It was concluded that conduction disturbances are predominantly atrioventricular in inferior and intra-ventricular in anterior MI; conduction disturbances are associated with increased risk of complications and death. Anterior location of MI may have an independent risk attribute.

Adult↗
PubMed1995

24h withdrawal following repeated administration of caffeine attenuates brain serotonin but not tryptophan in rat brain: implications for caffeine-induced depression.

Caffeine injected at doses of 20, 40 and 80 mg/kg increased brain levels of tryptophan, 5-hydroxytryptamine (5-HT) and 5-hydroxyindole acetic acid (5-HIAA) in rat brain. In view of a possible role of 5-HT in caffeine-induced depression the effects of repeated administration of high doses of caffeine on brain 5-HT metabolism are investigated in rats. Caffeine was injected at doses of 80 mg/kg daily for five days. Control animals were injected with saline daily for five days. On the 6th day caffeine (80 mg/kg) injected to 5 day saline injected rats increased brain levels of tryptophan, 5-HT and 5-HIAA. Plasma total tryptophan levels were not affected and free tryptophan increased. Brain levels of 5-HT and 5-HIAA but not tryptophan decreased in 5 day caffeine injected rats injected with saline on the 6th day. Plasma total and free tryptophan were not altered in these rats. Caffeine-induced increases of brain tryptophan but not 5-HT and 5-HIAA were greater in 5 day caffeine than 5 day saline injected rats. The findings are discussed as repeated caffeine administration producing adaptive changes in the serotonergic neurons to decrease the conversion of tryptophan to 5-HT and this may precipitate depression particularly in conditions of caffeine withdrawal.

Analysis of Variance↗
PubMed1995

Association of cytoskeletal proteins with estrogen receptor in rat uterine cytosol: possible role in receptor movement into the nucleus.

Evidence is presented to demonstrate a close association between an estrogen receptor or an estrogen receptor activation factor and the cytoskeletal proteins, tubulin and actin in rat uterine cytosol. Exposure of uterine cytosol to protein kinase assay medium resulted in the phosphorylation of three proteins, of molecular mass 55, 50 and 45 kDa. These 55 and 50 kDa proteins apparently represent tubulin, while the 45 kDa protein, is presumed to be actin. Phosphorylation of these proteins is under the regulatory influence of estradiol and the cyclic nucleotides, cAMP and cGMP. It is proposed that the protein kinase involved in this process may be the non-activated estrogen receptor (naER).

Actins↗
PubMed1994

Tolerance to diacetyl morphine antinociception: effects on brain serotonin.

The effects of 5 mg kg-1 diacetyl morphine (DAM) on brain serotonin metabolism of rats were investigated following tolerance to the antinociceptive effects of 2.5 mg kg-1 DAM. Brain levels of tryptophan and 5-hydroxy indoleacetic acid (5-HIAA) were higher in the DAM-tolerant rats killed 24 h after last daily administration of 2.5 mg kg-1 DAM. Administration of 5 mg kg-1 DAM produced less antinociception in DAM-tolerant than DAM-naive rats and increased brain tryptophan concentration in both tolerant and naive rats. 5-HIAA concentrations increased only in naive rats. Combined use of drugs interfering with brain 5-HT turnover along with opiates may be of future benefit for the treatment of chronic pain.

Analysis of Variance↗
PubMed1994

Enhancement of hepatic tryptophan pyrrolase activity and decreases of open field locomotion following single and repeated administration of high doses of caffeine in rats.

In view of a possible role of kynurenine in caffeine-induced anxiety syndrome, the effects of single and repeated administration of caffeine on hepatic tryptophan (T)-pyrrolase activity are investigated. Single administration of caffeine at doses of 80 mg/kg decreased open field locomotion and increased hepatic T-pyrrolase activity. Locomotor stimulating effects of 80 mg/kg caffeine, monitored in the home cages of rats, were attenuated following daily administration of caffeine for 5 days. Open field locomotor activity of rats and its caffeine-induced decrement were also attenuated following 5 daily administrations of caffeine on the 6th day. Basal levels of hepatic T-pyrrolase activity increased after 5 daily administrations of caffeine on the 6th day. Acute administration of caffeine did not further elevate hepatic T-pyrrolase activity in 5 day caffeine injected rats. Drug adjuvants decreasing hepatic T-pyrrolase activity may prove valuable for extending the clinical utility of caffeine.

Animals↗
PubMed1994

Characterization of biofilm and encrustation on ureteric stents in vivo.

OBJECTIVE: To examine the relationship between encrustation and microbial biofilm formation on indwelling ureteric stents. PATIENTS AND METHODS: Ureteric stents from 40 patients were examined for the presence of a microbial biofilm and encrustations. Bacteria in stent biofilms were isolated and identified. RESULTS: A profuse biofilm (> 10(4) c.f.u. cm-3) was identified on 11 (28%) stents. Enterococcus faecalis was the most common biofilm organism identified and Proteus spp. were not present. Encrustation was seen in 23 (58%) of stents and was not associated with the level of urinary calcium. The major risk factor for stent encrustation was the presence of urolithiasis. Importantly, there was no causative link between stent biofilm formation and encrustation. Both biofilm formation and encrustation increased with the duration of stenting. CONCLUSION: The results indicate that polyurethane is readily encrusted and colonized by bacteria in vivo despite antibiotic prophylaxis. Newer materials must be sought if effective long-term stenting is to be achieved.

Adult↗
PubMed1993

A four-step, inexpensive protocol for large-scale purification of goat uterine estrogen receptor.

A relatively inexpensive yet highly efficient and extremely rapid procedure has been developed for the isolation and purification of estrogen receptor from the goat uterine cytosol. Greater than 1 mg of purified receptor protein could be obtained from 75 g of uterine tissue within a period of < 24 h, following this protocol. The procedure does not require the use of an ultracentrifuge, a cold room, or a column chromatography setup. The entire isolation procedure, which involves adsorption to and selective elution from different chromatography matrices, is carried out at the laboratory bench using beakers kept in an ice bath. Antibodies raised against this receptor cross-react with the goat uterine estrogen receptor activation factor, a DNA binding protein having no capacity to bind estradiol but which dimerizes with the nonactivated estrogen receptor, an estrogen receptor incapable of binding to DNA on its own.

Animals↗
PubMed1993

Primary pulmonary hypertension: clinical, echocardiographic and haemodynamic features in 14 patients.

Clinical, echocardiographic and haemodynamic features in 14 patients (8 male and 6 females) with primary pulmonary hypertension, diagnosed by strict clinical and haemodynamic criteria are described. Age of the patients at diagnosis ranged from 11 years to 40 years with a mean of 23 years. The mean interval from onset of symptoms to diagnosis was 2.6 years. Common symptoms included dyspnoea on exertion (86%), fatigue (78%) and palpitation (78%). Raynaud's phenomenon was not encountered but one patient had signs and symptoms of left recurrent laryngeal nerve palsy. Pulmonary function studies showed mild restrictive ventilatory impairment (mean forced vital capacity 80% of predicted) with hypoxaemia and hypocapnea. The M-mode tracing of the pulmonary valve showed flat or negative E-F slope, a small or absent 'a' wave, and midsystolic notching in all the patients. Two-dimensional echocardiographic images showed a thickened right ventricular wall in 12(86%) patients; a normal to small left ventricular end-diastolic internal dimension in all the patients and right ventricular and right atrial enlargement in 78% of patients. Significant tricuspid regurgitation and pulmonary regurgitation was documented by Doppler interogation in 87% and 62% of patients examined respectively. Haemodynamic findings consisted of a marked rise of pulmonary artery pressure and pulmonary vascular resistance, low cardiac index and normal pulmonary artery wedge pressure. At cardiac catheterisation the mean right atrial pressure (mean +/- SD) was 9.8 +/- 4.8 mmHg; mean pulmonary artery pressure, 63.2 +/- 14.3 mmHg; cardiac index, 2.2 +/- 0.9 L/min. m2; and pulmonary vascular resistance index, 22.3 +/- 10.6 mmHg/L/min. m2; in these patients. No, death nor any sustained morbid events occurred during the diagnostic evaluation of the patients.

Adolescent↗
PubMed1992

Acute leukaemia in children--French-American-British (FAB) classification and its relation to clinical features.

A retrospective study of 45 patients of acute leukaemia in children (15 years age), in relation to FAB classification, is presented. Acute lymphoblastic leukaemias (ALL) were commoner than acute myeloid leukaemias (AML), with an ALL:AML ratio of 4.63:1. Amongst ALL, L1 was the most frequent type (59%), followed by L2 (35%) and L3 (5.4%), respectively. FAB types M2, M3, M4 and M5 were diagnosed in 2 patients each. An analysis of clinical features in relation to FAB classification is also presented.

Acute Disease↗
PubMed1989

Primary aortoduodenal fistula. Diagnosis by computed tomography.

A primary fistula between the abdominal aorta and the duodenum is rare and usually fatal. Computed tomography in a symptomatic but stable patient enabled preoperative evaluation and even diagnosis of abnormal communications, real or incipient, between the vascular and enteric system. This case demonstrated the effectiveness, ease, and low cost of documenting a primary aortoduodenal fistula. Surgical results were ultimately improved by initiating early intervention and aggressive management. Therapeutic principles included early intervention with aneurysmectomy, duodenorrhaphy, and extra-anatomic bypass. Anatomic graft placement may be acceptable in selected cases.

Aorta, Abdominal↗
PubMedDate not supplied

Continuous speech recognition for clinicians.

The current generation of continuous speech recognition systems claims to offer high accuracy (greater than 95 percent) speech recognition at natural speech rates (150 words per minute) on low-cost (under $2000) platforms. This paper presents a state-of-the-technology summary, along with insights the authors have gained through testing one such product extensively and other products superficially. The authors have identified a number of issues that are important in managing accuracy and usability. First, for efficient recognition users must start with a dictionary containing the phonetic spellings of all words they anticipate using. The authors dictated 50 discharge summaries using one inexpensive internal medicine dictionary ($30) and found that they needed to add an additional 400 terms to get recognition rates of 98 percent. However, if they used either of two more expensive and extensive commercial medical vocabularies ($349 and $695), they did not need to add terms to get a 98 percent recognition rate. Second, users must speak clearly and continuously, distinctly pronouncing all syllables. Users must also correct errors as they occur, because accuracy improves with error correction by at least 5 percent over two weeks. Users may find it difficult to train the system to recognize certain terms, regardless of the amount of training, and appropriate substitutions must be created. For example, the authors had to substitute "twice a day" for "bid" when using the less expensive dictionary, but not when using the other two dictionaries. From trials they conducted in settings ranging from an emergency room to hospital wards and clinicians' offices, they learned that ambient noise has minimal effect. Finally, they found that a minimal "usable" hardware configuration (which keeps up with dictation) comprises a 300-MHz Pentium processor with 128 MB of RAM and a "speech quality" sound card (e.g., SoundBlaster, $99). Anything less powerful will result in the system lagging behind the speaking rate. The authors obtained 97 percent accuracy with just 30 minutes of training when using the latest edition of one of the speech recognition systems supplemented by a commercial medical dictionary. This technology has advanced considerably in recent years and is now a serious contender to replace some or all of the increasingly expensive alternative methods of dictation with human transcription.

Dictionaries, Medical as Topic↗
PubMedDate not supplied

Management of diabetic foot--two years experience.

BACKGROUND: Diabetic foot is a serious complication of diabetes mellitus and may be the initial presentation of undiagnosed diabetes mellitus. A study of 48 patients with diabetic foot admitted in Surgical B Unit of Ayub Teaching Hospital over a period of two years is presented here. METHODS: This study was done to identify the risk factors and causative organisms in diabetic foot. This will help to lay down important principles of management of diabetic foot and highlight problems faced in the management of diabetic foot in our set up. RESULTS: There were 32 (66.6%) males and 16 (33.3%) females. The age incidence ranged from 30-70 years. Average length of hospital stay was 26 days. 2 patients had cellulitis, 6 patients had gangrene, 10 patients had ulcers and 15 patients had abscesses. 31 (64%) patients were cured by drainage of abscess and debridements alone. 17(36%) patients needed amputations. Peripheral neuropathy was the commonest risk factor. Staphylococcus aureus was the most common organism isolated from cultures (54%). CONCLUSIONS: Early hospitalization, effective glycaemic control, aggressive debridements and patient education in foot care can minimize diabetic foot diseases.

Adult↗