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Biomedical subjects

R Hawkins

Publications and source records attributed to R Hawkins.

17 recordsLinked to original sources
PubMed1992

Detection of spores of Bacillus anthracis using the polymerase chain reaction.

The polymerase chain reaction (PCR) was used to identify spores of Bacillus anthracis. By using an assay capable of amplifying a 1247-bp fragment from the gene that encodes the edema factor of B. anthracis, as few as 10(3) copies of a plasmid containing the edema factor gene and as few as 2 x 10(4) spores were detected. Subjecting the product of this PCR to a second PCR designed to amplify a 208-bp fragment nested within the 1247-bp product improved detection to a single plasmid copy per PCR and to two spores of B. anthracis per PCR.

Bacillus anthracis↗
PubMed1991

Renal ultrasound abnormalities in children with end-stage liver disease--reversal by liver transplantation.

Ultrasound (US) imaging of the kidneys was performed in 43 pediatric patients with end-stage liver disease evaluated for orthotopic liver transplantation. Renal size was increased in 8 patients (19%) and echogenicity of the kidneys was increased in 12 patients (28%). In 12 patients studied after liver transplantation, US revealed normal renal size in all and increased echogenicity in only 2 patients shortly after transplantation. Normalization of renal US findings was also found in 2 patients studied before and after liver transplantation. The glomerular filtration rate varied from 65 to 225 ml/min per 1.73 m2 in 5 patients with abnormal US, and from 74 to 116 ml/min per 1.73 m2 in 3 patients with normal US. Nephromegaly and increased echogenicity on renal US are frequent in children with end-stage liver disease and appear to be mostly reversible by liver transplantation.

Adolescent↗
PubMed1990

Evaluation of kidney function in renal transplant patients receiving long-term cyclosporine.

We prospectively assessed renal function in a group of 29 renal transplant patients receiving cyclosporine (CsA) in order to determine the course of their renal function over time and the relationship between different markers of glomerular function. We measured serum creatinine, DPTA, and creatinine clearances, and urinary albumin excretion. The clinical course of 24 patients (83%) permitted repeat studies over a period of 32 +/- 1 (SEM) months, and in these patients DTPA clearance, creatinine clearance, and the serum creatinine concentration did not vary with time. Five of the patients (17%) lost their grafts and returned to dialysis. On initial evaluation patients who lost their grafts had a lower DPTA clearance than those whose function was maintained (29 +/- 3 v 46 +/- 2 mL/min/1.73 m2 body surface area [BSA], respectively, P less than 0.005) and all of them had a DTPA clearance of less than 40 mL/min/1.73 m2 BSA. There was an inverse correlation between the log of the urinary albumin excretion and the DTPA clearance (n = 33, r = -0.59, P less than 0.001), a direct correlation with the serum creatinine concentration (N = 33, r = 0.89, P less than 0.0001), but no correlation with time after transplantation. Thus, despite the continued use of CsA, renal function over time was stable in patients who underwent repeated studies, as was the relationship between the DTPA clearance and the clinically used markers of transplant function, the serum creatinine concentration, and the creatinine clearance.

Albuminuria↗
PubMed1990

An unusual case of variegate porphyria with possible homozygous inheritance.

We report an unusual case of variegate porphyria in a young girl with epilepsy, mental retardation and premature adrenarche. Symptoms of porphyria commenced about the age of 12 years and death occurred about 18 months later. The patient had very low protoporphyrinogen oxidase activity in her cultured fibroblasts. Both parents had half the normal activity of this enzyme in lymphocytes and are heterozygous for the abnormal gene for variegate porphyria. Therefore, it is possible that the patient was a homozygous variant. Anticonvulsant therapy and low hepatic 5 alpha reductase activity were probably other contributing factors to the severity of the condition in this patient.

Animals↗
PubMed1979

Occupational asthma in an electronics factory.

Workers in a modern electronics factory were surveyed by questionnaire and lung function testing to see if there was evidence of widespread work-related respiratory symptoms. Of the responding workers exposed to solder flux fumes on the shop floor, 22% had work-related breathlessness or wheeze or both. Exposed workers had a lower FEV1 and FVC than unexposed workers. Work-related rhinitis was also present in 22% of exposed workers. The most likely cause for these results is sensitivity to colophony fumes, released from solder flux during soldering. Levels of solder flux fume were below the threshold limit value in this factory during the survey.

Adult↗
PubMed1978

Circadian rhythm of lithium toxicity in mice.

The existence of cyclical (circadian) variations in lithium toxicity in mice was determined. Mice, standardized to a light-dark cycle, were injected with lithium chloride (940 mg/kg) at one of six times (20:00, 24:00, 4:00, 8:00, 12:00, and 16:00) and subsequently observed for mortality over 28 h. A significant (P less than 0.01) time-of-day effect was found for lithium-induced lethality, with highest lethality following injection at 12:00.

Animals↗
PubMed1977

Studies in chronic allergic bronchopulmonary aspergillosis. 1. Clinical and physiological findings.

This report outlines the clinical and physiological features in 50 asthmatic patients with chronic allergic bronchopulmonary aspergillosis in whom the diagnosis was made from 2 to 25 years ago (mean duration 10-9 years). From a questionnaire and analysis of the peak expiratory flow rate measurements it was found that they were worse in the winter months, corresponding to the maximal concentrations of Aspergillus fumigatus in the atmosphere. Nineteen patients reported daily sputum production of up to an eggcupful or more, and 24 had noticed sputum 'plugs' in the previous year. Reduction of vital capacity (VC) was found in 20 patients, of forced expiratory volume in one second (FEV1) in 38 patients, and of maximal expiratory flow at 50% VC breathing air (V50air) in 47 patients. Nine patients had significantly reduced gas transfer factor (DLCO). Significant improvement (more than 15%) in FEV1 after inhaled bronchodilator was shown by only 17 patients. There were statistically significant correlations between the degree of reduction in the physiological measurements of VC, FEV1, and V50air with the age of the patient at the time of the study and the later in life the diagnosis of aspergillosis was made, whereas the reduction in DLCO was also significantly related to the duration of aspergillosis. Prospective studies are needed for a proper assessment of any protective effect of treatment on the pathophysiological changes due to the disease over many years.

Adult↗
PubMed1977

Studies in chronic allergic bronchopulmonary aspergillosis. 3. Immunological findings.

Precipitin tests by two different methods, double-diffusion (DD) and counterimmunoelectrophoresis (CIE), and measurements of total and specific IgE against Aspergillus fumigatus were made in 50 patients with chronic allergic bronchopulmonary aspergillosis and in three control groups--atopics with a positive immediate prick test to A. fumigatus but no evidence of allergic aspergillosis, atopics with a negative prick test to A. fumigatus, and non-atopics. Precipitins were found in 84% and 78% of the patients with aspergillosis by the DD and CIE methods respectively. Precipitins were also found in 6 out of 27 (22%) patients with a positive prick test to A. fumigatus but no evidence of aspergillosis and in 1 of 24 patients with a negative prick test to A. fumigatus. The means of specific and total IgE values were significantly higher in the group of patients with aspergillosis than in the three other groups of patients. The increase in specific but not total IgE showed a statistically significant correlation with positive precipitin tests in the patients with aspergillosis. Total IgE but not specific IgE values were significantly higher (0-02 less than P less than 0-05) in patients who had had a transient radiographic shadow in the previous three months. Positive precipitin tests were also significantly correlated with the number of transient shadows in the past and with the interval of time since the last transient shadow.

Aspergillosis↗
PubMed1977

Studies in chronic allergic bronchopulmonary aspergillosis. 4. Comparison with a group of asthmatics.

A comparison is made of lung function tests and radiographic findings in 20 asthmatic patients with allergic bronchopulmonary aspergillosis paired in terms of sex, age, and duration of asthma with 20 other asthmatics in whom the diagnosis of aspergillosis was excluded in order to see if the aspergillosis causes more lung damage. One hundred per cent of the patients with aspergillosis and 75% of the patients with asthma alone showed a significantly reduced forced expiratory volume in one second (FEV1) before bronchodilator. All the patients in the two groups had a significantly reduced maximal expiratory flow at 50% vital capacity breathing air (V50air) but the severity of the reduction was statistically greater in the aspergillosis group. Reversibility in FEV1 of 15% and more was found in 50% of patients with asthma alone as against 31% of patients with aspergillosis. The degree of reversibility of FEV1 was also statistically greater in patients with asthma alone. Improvement of less than 20% of V50 after helium-oxygen breathing was found in 33% of the patients with asthma alone and in 75% of the patients with aspergillosis. Patients with aspergillosis also showed significantly (0-001 less than P less than 0-01) more reduced gas transfer factor. Radiological features of overinflation were as common in the two groups. Tubular and ring shadows were found in 95% and 60% respectively of patients with aspergillosis as against 45% and 15% of patients with asthma alone.

Adult↗
PubMed1976

Chorionic somatomammotrophin as index of fetal growth.

Concentrations of chorionic somatomammotrophin (hCS) in maternal plasma at the time of delivery and in placental extracts were determined by radioimmunoassay and related to neonatal growth in 111 normal pregnancies. Mean maternal plasma hCS concentration was lower in association with small-for-dates infants, defined by either height or weight, than with well-grown preterm or term infants. Mean placental hCS concentration was not decreased in association with undergrown infants though placental hCS was correlated with maternal hCS (r=0 - 245).

Birth Weight↗
PubMedDate not supplied

Measurement of regional brain glucose utilization in vivo using [2(-14)C] glucose.

A new technique is described for the autoradiographic determination of regional brain glucose metabolism employing 14C labeled glucose as substrate and measurement principles previously described for whole brain. Regional glucose values correlate closely with those reported for the 14C-deoxyglucose technique. The method has the advantages of 1) a much shorter experimental period, 2) a relatively simple mathematical treatment, and 3) the utilization of the actual, fully metabolizable substance itself, glucose, as the label. In addition to normal rats, regional values are reported for 20 individual brain areas of rats in bicuculline induced status epilepticus, rats intoxicated with ammonium and rats anesthetized with pentobarbital sodium or ketamine.

Animals↗