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Biomedical subjects

T S Brown

Publications and source records attributed to T S Brown.

At least 19 recordsLinked to original sources
PubMed2005

Linkage between proton binding and folding in RNA: implications for RNA catalysis.

Small ribozymes use their nucleobases to catalyse phosphodiester bond cleavage. The hepatitis delta virus ribozyme employs C75 as a general acid to protonate the 5'-bridging oxygen leaving group, and to accomplish this task efficiently, it shifts its pKa towards neutrality. Simulations and thermodynamic experiments implicate linkage between folding and protonation in nucleobase pKa shifting. Even small oligonucleotides are shown to fold in a highly co-operative manner, although they do so in a context-specific fashion. Linkage between protonation and co-operativity of folding may drive pKa shifting and provide for enhanced function in RNA.

Base Sequence↗
PubMed2001

Rheumatoid neutrophilic dermatitis in a woman with seronegative rheumatoid arthritis.

Rheumatoid neutrophilic dermatitis (RND) is an unusual cutaneous reaction in patients with rheumatoid arthritis (RA). RND is characterized by symmetric, erythematous papules, plaques, nodules, and urticarial lesions often located over the joints, extensor surfaces of the extremities, or the trunk. This entity demonstrates an intense neutrophilic dermal infiltrate without vasculitis. All patients previously reported with RND had severe RA with relatively high titers of rheumatoid factor when tested. A 67-year-old woman had a 2-month history of multiple, tender, 4 to 8 mm erythematous, crusted papules and nodules that occurred in clusters on her anterior thighs, knees, and legs. She suffered from severe disabling seronegative RA. RND may complicate seronegative RA.

Aged↗
PubMed2000

Cavitating pulmonary infiltrate in an adolescent with pyoderma gangrenosum: a rarely recognized extracutaneous manifestation of a neutrophilic dermatosis.

Neutrophilic dermatoses such as pyoderma gangrenosum are characterized by sterile, neutrophilic cutaneous infiltrates. Extracutaneous neutrophilic infiltrates can occur, primarily in the joints, lungs, heart, central nervous system, gastrointestinal tract, and eyes. Pulmonary disease is the most frequently reported extracutaneous manifestation of pyoderma gangrenosum and is characterized by patchy infiltrates or interstitial pneumonitis. We describe an adolescent with typical pyoderma gangrenosum who presented with cavitary pneumonia and responded completely to oral corticosteroids. In patients with inflammatory ulcers, extracutaneous neutrophilic disease should be considered, once an infectious process has been excluded.

Adolescent↗
PubMed1999

Atypical presentation of herpes simplex virus in a patient with chronic lymphocytic leukemia.

Perianal infections caused by herpes simplex virus are common in immunocompromised patients. The cutaneous presentation in these patients is often atypical, overlaps with the clinical features of other diseases, poses a difficulty in diagnosis, and responds poorly to treatment. An immunocompromised patient with chronic lymphocytic leukemia, treated with oral corticosteroids, presented with chronic perianal ulcerations. This patient was referred for evaluation and treatment of "recalcitrant" pyoderma gangrenosum. Prompt diagnosis was possible when the clinical features were recognized and appropriate biopsy and cultures were obtained. We describe an atypical presentation of herpes simplex virus associated with both an endogenous and exogenous induced immunodeficiency, and stress the importance of routinely performing cultures on all perianal ulcerations and anal fissures to avoid the misdiagnosis, inappropriate treatment, and prolonged discomfort of these afflicted patients.

Aged↗
PubMed1998

Transthoracic needle biopsy for suspected thoracic malignancy in elderly patients using CT guidance.

There are few reports of transthoracic needle biopsy (TNB) in elderly (>70 years) patients although there is some evidence that age may be a risk factor in developing pneumothorax. We report our experience of 38 patients, age range 70-90 years, who underwent computed tomography (CT)-guided TNB for suspected malignancy of the chest, with particular reference to sensitivity and complication rate following the procedure. The biopsy was obtained using either a spinal needle or, if appropriate, a core of tissue was obtained using a cutting needle. The biopsy showed evidence of malignancy in 27 patients. Pneumothorax occurred in 10 of 40 biopsies. Two patients with pneumothorax required pleural drains; one was discharged the following day and the other required drainage for 3 days. Haemoptysis was not a problem but occurred as a transient postbiopsy event in three patients. In 26 of 40 (65%) episodes the patients were sent home within 24 h of the diagnostic procedure. It is thus quite possible to undertake the procedure on a day case basis. CT-guided TNB is a safe and reliable procedure in elderly patients with suspected chest malignancy and is well tolerated.

Aged↗
PubMed1994

Leukocytosis in labor: what are its implications?

OBJECTIVE: The objective of this study was to determine the usefulness of the peripheral white blood count (WBC) drawn during labor as a predictor of postpartum morbidity. METHOD: Hospital charts on 309 consecutive obstetrical deliveries performed by residents of the Cox Family Practice Residency were reviewed for evidence of maternal or neonatal postpartum morbidity. An analysis of means was used to compare the average antepartum WBC in the morbid and non-morbid groups. RESULTS: The average WBC in a laboring patient was 12,450, with a range of 4,400 to 29,100. Patients with postpartum complications had a WBC similar to that of patients without complications (12,900 vs 12,300 p = 0.449). CONCLUSION: An elevated WBC obtained on admission to the labor ward is not helpful in predicting postpartum complications in mothers or newborns.

Adolescent↗
PubMed1993

Breast imaging in women under 35 with symptomatic breast disease.

With the increasing utilization of mammography, young women under the age of 35 are being referred for mammographic examination more frequently. A review of the mammograms of 159 consecutive patients aged under 35 was conducted to evaluate the clinical value of the examination in the age group for whom the probability of malignancy is low. 74% of patients referred had no discrete palpable mass and presented predominantly with lumpy or tender breasts, the remaining 24% had a discrete palpable mass. In neither group did radiographic examination beneficially influence clinical management. We propose protocol where no imaging is performed in women under 35 in the absence of a palpable mass unless there is a localized bloody discharge or a strong family history or previous personal history of breast cancer. In patients with a palpable mass, ultrasound should be performed initially to identify simple cysts and if negative only then progressing to mammography.

Adult↗
PubMed1992

Aluminum accumulation in serum, liver and spleen of Fe-depleted and Fe-adequate rats.

The study described here was planned to test the hypothesis that Al absorption and accumulation in the body are inversely related to Fe status. Aluminum3+ and Fe3+ have similar ionic radii and charge densities, pH-solubility relationships, and affinities for ligands, such as citrate and transferrin. Male weanling Sprague-Dawley rats were pair fed an Fe-deficient or Fe-adequate (control) diet for 2 wk. Each diet group was then randomly assigned to receive for four more weeks the Fe-deficient or adequate diet with: 1. 2% AlCl3; 2. AlCl3 + 3.5% Na citrate; or 3. No Al or citrate. Iron depletion, confirmed by measurements of hemoglobin, hematocrit, serum Fe, and Fe binding capacity, increased concentrations of serum, liver, and spleen Al in all groups fed AlCl3. However, the increase owing to Fe deficiency was significant only when Al was fed with citrate. The data suggest that Fe deficiency enhances both Al absorption and accumulation in liver and spleen.

Administration, Oral↗
PubMed1987

Tuberculosis affecting the oesophagus.

Three Asian patients presenting with dysphagia were shown to have oesophageal involvement secondary to adjacent tuberculous mediastinal lymph nodes. The findings included fistula between the oesophagus and the tracheobronchial tree and extrinsic compression of the oesophagus. These cases reflect the increasing incidence of mediastinal lymphadenopathy in adult tuberculosis, especially in our immigrant community.

Adult↗
PubMed1987

Double-blind, placebo-controlled trial of twice-daily nifedipine as a step-2 agent in mild essential hypertension.

Nifedipine is a calcium-channel blocker that produces vasodilatation and decreased peripheral resistance in humans. Several clinical reports document blood-pressure-lowering effects of nifedipine with either acute or chronic administration. Little data are available to evaluate sustained-release nifedipine as a step-2 agent. We performed a multicenter double-blind, placebo-controlled trial of twice-daily nifedipine in the treatment of mild essential hypertension not controlled by diuretic alone. Seventy-one subjects completed 8 weeks of treatment with nifedipine or placebo in combination with a stable dose of diuretic. Treatment groups were comparable with respect to age, sex, race, duration of hypertension, and pretreatment weight. Baseline supine blood pressure was no different in the two treatment groups (144 +/- 15/98 +/- 6 mmHg in the nifedipine/diuretic-treated group and 145 +/- 16/98 +/- 6 mmHg in the placebo/diuretic-treated group). After 8 weeks of treatment, supine blood pressure was 132 +/- 11/88 +/- 6 mmHg in the nifedipine/diuretic-treated group and 140 +/- 16/92 +/- 8 mmHg in the placebo/diuretic-treated subjects (p less than 0.01 for both systolic and diastolic blood pressure when compared to placebo/diuretic). Nifedipine with diuretic had similar effects on standing blood pressure. Nifedipine/diuretic decreased blood pressure from baseline values within 1 week of treatment, and the effect persisted for 8 weeks. Heart rate increased in nifedipine/diuretic-treated subjects during the first 2 weeks of treatment but returned to baseline by 4 weeks. No laboratory abnormalities could be attributed to nifedipine/diuretic treatment. Side effects were mild and infrequent. In summary, nifedipine/diuretic is effective and well tolerated in the treatment of uncomplicated essential hypertension inadequately controlled with diuretic therapy alone.

Adult↗
PubMed1980

Tuberculosis of the ribs.

The radiological appearances of seven cases of rib tuberculosis are discussed. The combination of rib destruction and an extrapleural soft tissue opacity in an Asian immigrant makes tuberculosis a highly likely diagnosis. The presence of an associated fluctuant chest wall swelling, enables a diagnosis of tuberculosis to be made with confidence even in Caucasians.

Adolescent↗
PubMed1980

Tuberculous mediastinal lymphadenopathy in Bradford.

During the calendar year 1978, 18 patients who commenced treatment for pulmonary tuberculosis in the Bradford Chest Clinic were found to have enlarged mediastinal lymph glands. Sixteen of these 18 patients were adults who thus presented radiographic patterns which have been classically regarded are representing primary tuberculous infection and are usually seen in children but only rarely in adults. All 16 adult patients were immigrants of either Indian or Pakistani origin. Tuberculosis is therefore a common cause of mediastinal lymphadenopathy in the immigrant population and in view of the successful response to therapy it should be considered ahead of the more usual diagnoses of lymphoma, sarcoidosis or metastatic carcinoma.

Adult↗
PubMed1980

Tuberculosis of the skull vault.

Tuberculosis of the skull vault is very rare and recently has only been reported from Africa. Two cases have presented in the city of Bradford during the past 10 years, both in young Asians. The radiology is discussed.

Adolescent↗
PubMed1979

Plasma corticosterone levels and ulcer formation in rats with hippocampal lesions.

In order to examine the effects of hippocampal lesions on plasma corticosterone levels and ulcer formation, 4 conditions were studied: (1) unrestrained nondeprived (2) unrestrained 24 h food-deprived (3) simple restraint and (4) restraint plus intermittent shock. In the unrestrained and unrestrained plus 24 h food-deprived conditions, neither animals with hippocampal lesions nor control animals developed ulcers. In both instances plasma corticosterone levels were similar in experimental and control animals. Differences appeared in the simple restraint and restraint plus intermittent shock conditions. In both of these conditions animals with hippocampal lesions developed more ulcers and had a higher corticosterone level than controls. It is concluded that animals with hippocampal lesions show an enhanced reaction to stress.

Animals↗