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Biomedical subjects

R Hamid

Publications and source records attributed to R Hamid.

At least 37 records · Page 2Linked to original sources
PubMed2002

Pitfall in insertion of suprapubic catheter in patients with spinal cord injuries.

OBJECTIVE: To report an unusual presentation of a misplaced suprapubic catheter (SPC) in a spinal cord injury (SCI) patient. DESIGN: A case report of a SCI patient in whom a SPC was 'partially misplaced' in an emergency. SETTING: London Spinal Injuries Unit, Stanmore, UK. SUBJECT: A 33-year-old man who sustained a C5 SCI in a road traffic accident 6 months ago. He had an indwelling urethral catheter, which blocked off and repeated attempts to reinsert another one per urethra were unsuccessful. MAIN OUTCOME MEASURE: A SPC was inserted in an emergency at the bedside, as he developed autonomic dysreflexia. The catheter initially drained clear urine but subsequently the flow became intermittent. He also started complaining of lower abdominal discomfort. RESULTS: The abdominal examination was unremarkable without signs of peritonism. An ultrasound scan of the abdomen revealed the eye of the catheter in the bladder but the balloon had been inflated in the subcutaneous tissues. It was reinserted under cystoscopic control in the operating theatre. CONCLUSION: The insertion of a SPC in a neuropathic patient can be a challenge even for an experienced urologist. As these patients often have small capacity bladders, the SPC should be inserted under cystoscopic control wherever possible. However if they are inserted blindly there should be a high index of suspicion for the potential complication of a misplaced catheter. The patient should undergo regular abdominal examination and an ultrasound scan should be performed as soon as possible for confirmation.

Abdominal Pain↗
PubMed2002

Penile cancer: an overview.

Carcinoma of the penis affects 1 in 100,000 men per year in most developed countries. It accounts for less than 1% of adult malignancies in Europe and the USA. Survival is excellent if diagnosed early, but most men present up to 1 year after the initial lesion is noted. Unfortunately the treatment of metastatic disease is still disappointing.

Carcinoma in Situ↗
PubMed2001

Female genital tuberculosis revisted.

OBJECTIVE: To assess the clinical presentation of genital tuberculosis and to study various modes of diagnosis and treatment. SETTING: The Aga Khan University Hospital (AKUH), Karachi. METHOD: A retrospective case review of all index female cases of genital tuberculosis, admitted to AKUH over twelve years of period. RESULT: A total of 40 cases of genital tuberculosis were reported during this time period. Majority of cases were between 25-45 years. The commonest presenting symptoms were infertility (42.5%) and abdominal pain (42%). Others included fever, ascites, irregular vaginal bleeding, oligomenorrhea, chest pain and pain in the flanks. Main mode of treatment was antituberculous drug therapy for duration of nine months. Only 3 patients had successful pregnancies. CONCLUSION: Genital tuberculosis should be excluded when managing infertility in females.

Abdominal Pain↗
PubMed2001

Maternal deaths in a developing country: a study from the Aga Khan University Hospital, Karachi, Pakistan 1988-1999.

OBJECTIVE: The maternal deaths occurring over a twelve-year period (1988-1999) in a tertiary referral center were reviewed. The purpose of the study was to assess the causes of these maternal deaths. SETTING: The Aga Khan University Hospital (AKUH) Karachi, Pakistan. METHODS: The medical records of maternal deaths were reviewed. These were women who had either registered for delivery at the hospital; or were referred from another hospital or from home, when an emergency developed. They were either admitted to the Medicine, Surgery and the Obstetrics and Gynaecology Departments at the hospital. RESULTS: A total of 81 maternal deaths were identified, of which five were the registered patients. Causes of deaths were eclampsia, puerperal sepsis and pulmonary embolism. The maternal mortality ratio in the registered patients was 20 per 100,000 live births. Ninety percent of the women were between the age group of 15-35 years. Of these forty two percent were primigravidas, forty four percent of the women died due to direct causes, of which sepsis was the most common cause and accounted for twenty five percent of the total deaths. Indirect causes were responsible for 55.6% of the deaths, including hepatic failure in 21%, other infectious disease in 17% and malignancy in 5% of the cases. CONCLUSION: In developing countries other than obstetrical causes, infectious diseases contribute to the death of women during childbearing years. Comprehensive medical services and adequate obstetrical emergency services can lower maternal mortality rates at all levels.

Adolescent↗
PubMed1999

Trends in injection risk behaviors in a sample of New York City injection drug users: 1992-1995.

OBJECTIVES: This study assessed the relation between year of recruitment into an AIDS prevention project and likelihood of engaging (yes/no) in injection risk behaviors. METHODS: In total, 834 injection drug users were recruited over a 44-month period (January 1992-August 1995) in New York City. Logistic regression was used to examine trends in three behaviors, across four successive annual cohorts: using needles/syringes that were previously used by another person, using injection supplies (e.g., cookers, cotton, rinse water) that had been previously used, and giving or lending of used needles/syringes to another person. RESULTS: Significant (p < .0001) decreasing trends occurred in two behaviors: giving or lending of used needles/syringes to another person and use of injection supplies that had been used by another person. Sample characteristics were generally consistent over time and did not obviate significant injection risk trends. CONCLUSIONS: Decreasing trends in injection risk behaviors could not be explained by changing sample characteristics. Even though some injectors report engaging in risky injection practices, the confluence of numerous AIDS prevention efforts in the 1990s has contributed to an overall reduction in the likelihood of such behaviors.

Adult↗
PubMed1999

The effects of oxytocin on the pattern of electrical propagation in the isolated pregnant uterus of the rat.

In the isolated pregnant myometrium of the rat, the pattern of propagation was investigated by recording simultaneously from 240 different extracellular sites while the contraction of the tissue was recorded isometrically. Analysis of all recorded electrograms allowed the two-dimensional spread of activity in the myometrium to be reconstructed. From these activation maps, the conduction velocities were measured in the longitudinal, oblique and transversal directions. At low concentrations (10(-9 )and 5x10(-9) M), oxytocin significantly increased the frequency and duration of electrical bursts and the average spike intervals, without affecting the homogeneity of action potential propagation, concomitant with a significant increase in the amplitude of contractions. At high concentrations (10(-8) and 5x10(-8) M), oxytocin induced conduction blocks and the size of inexcitable areas was increased, concomitantly with an increase in muscle contractures. In contrast, the conduction velocities in the longitudinal, oblique and circular directions were not influenced by oxytocin at any concentrations.

Action Potentials↗
PubMed1999

Chemoprevention of colonic aberrant crypt foci by an inducible nitric oxide synthase-selective inhibitor.

Inducible nitric oxide synthase (iNOS) is overexpressed in colonic tumors of humans and also in rats treated with a colon carcinogen. iNOS appear to regulate cyclooxygenase-2 (COX-2) expression and production of proinflammatory prostaglandins, which are known to play a key role in colon tumor development. Experiments were designed to study the inhibitory effects of S,S'-1,4-phenylene-bis(1,2-ethanediyl)bis-isothiourea (PBIT) a selective iNOS-specific inhibitor, measured against formation of azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF). Beginning at 5 weeks of age, male F344 rats were fed experimental diets containing 0 or 50 p.p.m. of PBIT, or 2000 p.p.m. of curcumin (non-specific iNOS inhibitor). One week later, rats were injected s.c. with AOM (15 mg/kg body wt, once weekly for 2 weeks). At 17 weeks of age, all rats were killed, colons were evaluated for ACF formation and colonic mucosa was assayed for isoforms of COX and NOS activities. Both COX and iNOS activities in colonic mucosa of the AOM-treated rats were significantly induced. Importantly, 50 p.p.m. PBIT suppressed AOM-induced colonic ACF formation to 58% (P < 0.0001) and crypt multiplicity containing four or more crypts per focus to 78% (P < 0.0001); it also suppressed AOM-induced iNOS activity. Curcumin inhibited colonic ACF formation by 45% (P < 0.001). These observations suggest that iNOS may play a key regulatory role in colon carcinogenesis. Developing iNOS-specific inhibitors may provide a selective and safe chemopreventive strategy for colon cancer treatment.

Animals↗
PubMed1999

Agreement between urinalysis and self-reported drug use.

One hundred fifty-eight drug users received an interview that included self-reported drug use. Opiate/cocaine use in the prior 48 hours was assessed by urinalysis. Fifty-five subjects received a urine test after the interview and 103 were tested before. Chi-square tests were performed to determine if agreement between self-reported drug use and urine test results was associated with timing of urine testing. The rate of agreement was 58% when the urine test was performed after the interview and 93% when performed before the interview (chi2 = 28.6, p < .001). Conducting urine tests before an interview can increase the accuracy of self-reports.

Adult↗
PubMed1999

Inhibition by dietary menhaden oil of cyclooxygenase-1 and -2 in N-nitrosomethylurea-induced rat mammary tumors.

Studies in laboratory animals and epidemiological surveys suggest a relationship between the type and amount of dietary fat and mammary cancer. One mechanism proposed to explain this relationship is modulation by dietary fat, of mammary tumor eicosanoid levels through action at the rate limiting enzyme in eicosanoid synthesis, cyclooxygenase (COX). Until recently there have been no studies which have examined COX gene expression in human breast or rodent mammary tissues. In this study we have demonstrated the presence of two immunoreactive isoforms of cyclooxygenase (COX-1 and -2), and the modulating effects of n-3 fatty acids on their expression, in N-nitrosomethylurea (NMU)-induced rat mammary tumors. Three different high fat diets were compared namely, corn oil (CO) 23%; CO 18% menhaden oil (MO) 5%; CO, 5%/MO 18%; low fat corn oil (5%) served as a control. It was found that immunoreactive COX-2 protein levels were approximately 3x higher than COX-1 levels in NMU-induced mammary tumors. Moreover, the high menhaden oil diet (rich in n-3 fatty acids) significantly suppressed both COX-1 (-28%) and COX-2 (-36%) protein levels when compared to the high corn oil diet. No differences were found among the other treatment groups when compared pair-wise or with low-fat control. The mechanism(s) by which n-3 fatty acids suppress COX-1 and COX-2 remain to be determined.

Animals↗
PubMed1999

Human mutations and their detection by gene and linkage analysis, allele sharing and association methods.

It has been 20 years since DNA analysis was first used in the detection of sickle-cell anaemia. Here, techniques for detecting human mutations are reviewed. We describe direct detection of mutations using restriction enzyme analysis and polymerase chain reaction amplification to detect gene deletions, rearrangements and point mutations. Indirect detection of mutations include the use of DNA polymorphisms in linkage analysis.

Chromosome Mapping↗
PubMed1998

The initiation, continuation, and termination of spontaneous episodes of circus movements in the pregnant myometrium of the rat.

OBJECTIVES: The objectives of this study were to determine the mechanisms responsible for the initiation and the termination of episodes of circus movements and to describe the characteristics of these circuits in rat myometrium. STUDY DESIGN: By means of simultaneous recordings from 240 sites in Wistar rats at 17, 19, or 21 days' gestation, a spatial and temporal analysis was performed on the electrical activation from the beginning until the end of 22 episodes of circus movements. RESULTS: The initiation of reentry was caused by (1) transient unexcitable areas at the beginning of the burst or (2) lines of conduction blocks. Circus movements were terminated by (1) reversal of recruitment (decruitment) at the end of the burst, (2) occurrence of lines of conduction blocks, or (3) interruption of the circuit. On average circuits rotated for 6 revolutions during 2 seconds. In most cases circuits remained stable; sometimes circuits drifted along the tissue and occasionally multiple wavelets were seen instead of a single circuit. CONCLUSIONS: Spatial nonhomogeneities in conduction caused by transient unexcitable areas play a major role in both the initiation and the termination of episodes of circus movements in the pregnant rat myo-metrium. In addition, most circuits remained in a single location, although sometimes meandering or even fibrillatory activity was seen.

Animals↗
PubMed1998

A strategy for reducing the mortality rate from vasa previa using transvaginal sonography with color Doppler.

Vasa previa is a cause of sudden unanticipated fetal death, with a fetal mortality of 33-100%. Transvaginal sonography (TVS) and color Doppler may aid in making the diagnosis antenatally, allowing elective Cesarean delivery, thereby avoiding fetal death from exsanguination which would occur if the membranes were allowed to rupture in labor. Whilst it is not feasible to screen all pregnant women for vasa previa, antenatal examination with TVS and color Doppler of women at risk, specifically those with low-lying placentas, bi-lobed, multi-lobed and succenturiate-lobed placentas, multiple pregnancies and pregnancies resulting from in vitro fertilization may lead to antenatal diagnosis of the condition. We present the last three cases of vasa previa to have occurred in our institution, two of which were diagnosed antenatally using TVS and color Doppler. In all three cases, routine 20-week obstetric sonography revealed low-lying placentas; in only one of these did the placenta remain low at term. A low-lying placenta at 20 weeks may be a risk factor for vasa previa; we suggest that further studies be carried out to ascertain this. Judicious use of TVS and color Doppler in women considered at risk of vasa previa may help to reduce the mortality from this condition.

Cesarean Section↗
PubMed1998

Dietary fish oil inhibits the expression of farnesyl protein transferase and colon tumor development in rodents.

Although epidemiological and experimental studies indicate a strong relationship between different dietary fats and risk of colon cancer, the modulating effects of these nutritional factors at the molecular level are not fully elucidated. Activated ras genes have been implicated in the etiology of many human malignancies, including colon cancer. It is well established that the transforming ability of ras-p21 depends on its correct localization in plasma membrane. We have previously demonstrated that ingestion of a relatively higher amount of dietary fish oil leads to reduced plasma membrane levels of ras-p21 with concomitant increase in its cytoplasmic contents during the promotion and progression phases of chemically-induced colon tumorigenesis. In this follow-up experiment, we have found that intake of a high amount of corn oil, one of the most widely used fats in the American diet, enhances the expression of farnesyl protein transferase (FPTase). This enzyme catalyses farnesylation of ras precursors in a critical step during post-translational modification of ras oncoproteins, thereby enabling their anchorage to plasma membrane. In contrast, consumption of high amounts of fish oil, which is rich in omega-3 polyunsaturated fatty acids, reduces the levels of FPTase expression, thus inhibiting post-translational processing of ras precursors resulting in decreased ras function both in colonic mucosa as well as in colon tumors. These results correlate with increased incidence and multiplicity of grossly visibly colon tumors in carcinogen-treated animals fed a high corn oil diet versus decreased incidence and multiplicity of colon tumors in their counterparts fed the high fish oil diet. This dietary inhibition of FPTase may have a practical chemopreventive potential.

Alkyl and Aryl Transferases↗
PubMed1998

Urban crack users: gender differences in drug use, HIV risk and health status.

This study assessed gender differences in drug use, HIV risk, and health status in a sample of urban crack users. Using targeted sampling, 1434 crack users (66% male and primarily African-American and Puerto Rican), were recruited from the streets of East Harlem, New York City. A standardized, structured interview was administered, drug use was validated by urinalysis, and HIV testing was offered. Gender differences were observed on sociodemographic variables and patterns of drug use. Other than welfare, men and women cited different major sources of income. Women reported greater use of crack, and men were more likely to use injection drugs as well as crack. Data on sexual risk indicated that women had more sexual partners than men, but the percentage of unprotected vaginal sex for both men and women was greater for those who did not exchange sex for drugs and/or money. The number of persons already infected with HIV was substantial. Many reported histories of other sexually transmitted diseases which were generally higher among men. Future research should investigate the relationship between gender and other factors (e.g., ethnicity, geographic location) associated with HIV risk.

Adult↗