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Biomedical subjects

D Merrick

Publications and source records attributed to D Merrick.

8 recordsLinked to original sources
PubMed2006

Diabetes prevalence in England, 2001--estimates from an epidemiological model.

AIMS: To estimate the total prevalence of diabetes mellitus (diagnosed and undiagnosed) at national, regional and local level in England to support health-care planning and delivery. METHODS: An epidemiological model was constructed by applying age-sex-ethnic-specific reference prevalence rates from epidemiological studies to resident populations (2001 census) of England at national, regional, and local authority/Primary Care Trust levels. RESULTS: Estimated prevalence of total diabetes for all persons in England was 4.41% in 2001, equating to 2 168 000 persons. Type 2 diabetes was estimated to affect 2 002 000 persons (92.3%) and Type 1 diabetes 166 000 persons (7.7%). Diabetes prevalence was estimated to be higher in women (5.17%) than men (3.61%). People from ethnic minority groups had higher crude prevalence than White Europeans (4.29, 5.69, 6.63 and 2.13% among White Europeans, Black African/Caribbeans, South Asians and 'other' groups, respectively). Prevalence increased sharply with age (0.33, 3.37 and 13.92%, respectively, in those aged 0-29, 30-59 and 60+ years). The model allows use of user-defined population denominator estimates to derive numbers and prevalence of people with diabetes for a given local population group, such as at ward or general practice level. CONCLUSIONS: Self-reported diabetes prevalence estimates from community surveys underestimate the true burden of diabetes. The model can be used to derive the expected total prevalence of diabetes in health areas that lack reliable data to facilitate the implementation of the National Service Framework for diabetes. It will also allow estimates of future diabetes prevalence to be derived, and can potentially be used for prevalence estimates in all of the UK.

Adolescent↗
PubMed2005

The interrelation of demographic and geospatial risk factors between four common sexually transmitted diseases.

OBJECTIVES: To examine the interrelation between demographic and geospatial risk factors for gonorrhoea, chlamydia, genital warts, and genital herpes. DESIGN: We analysed age, sex, ethnicity, socioeconomic status, and area of residence for Leeds residents aged 15-54 with Neisseria gonorrhoeae, genital Chlamydia trachomatis, first episode genital herpes, and first episode genital warts during 1994-5. The 1991 UK census provided denominator population information. RESULTS: Regression analysis showed that young age (15-24 years), ethnicity (with a gradient of risk black >white >Asian), and residence in inner city areas of deprivation were independent risk factors for all STDs. There were highly significant correlations in the geospatial distribution of incidence rates between the four infections. However, there was variation in the degree of central urban clustering, with gonorrhoea having the most restricted, and genital warts and chlamydia the widest distribution. 31% of all disease occurred in the four inner city census wards, representing 15% of the population. CONCLUSION: These results are in keeping with core group theory applying in a unified manner to the four most common UK sexually transmitted diseases in this urban area. Population based studies are needed to clarify whether ethnicity is associated with differing sexual behavioural or mixing patterns. Our data suggest that chlamydia screening in women <25 years of age could detect 70% of cases in the community, that such programmes should give particular emphasis to implementation in core group areas, and that they could function as unifying strategies for the control of most common STDs within urban areas.

Adolescent↗
PubMed1988

Biochemical properties of sodium channels in a wide range of excitable tissues studied with site-directed antibodies.

Antibodies against a peptide (SP19) corresponding to a highly conserved, predicted intracellular region of the sodium channel alpha subunit bind rat brain sodium channels with a similar affinity as the peptide antigen, indicating that the corresponding segment of the alpha subunit is fully accessible in the intact channel structure. These antibodies recognize sodium channel alpha subunits from rat or eel brain, rat skeletal muscle, rat heart, eel electroplax, and locust nervous system. alpha subunits from all these tissues except rat skeletal muscle are substrates for phosphorylation by cAMP-dependent protein kinase. Disulfide linkage of alpha and beta 2 subunits was observed for both the RI and RII subtypes of rat brain sodium channels and for sodium channels from eel brain but not for sodium channels from rat heart, eel electroplax, or locust nerve cord. Treatment with neuraminidase reduced the apparent molecular weight of sodium channel alpha subunits from rat and eel brain and eel electroplax by 22,000-58,000, those from heart by 8000, and those from locust nerve cord by less than 4000. Our results provide the first identification of sodium channel alpha subunits from rat heart and locust brain and nerve cord and show that sodium channel alpha subunits are expressed with different subunit associations and posttranslational modifications in different excitable tissues.

Animals↗
PubMed1988

The Northwestern University Triplet Study. III: Neonatal outcome.

Limited data suggest that cesarean section (CS) may be the preferred method of delivery for triplets. Despite this, it is also felt that the third triplet is at great risk at delivery. We reviewed our experience of 14 triplet pregnancies at Northwestern University between 1981 and 1985. All deliveries were attended by neonatal teams in sufficient number to resuscitate each infant. Of the 14 pregnancies, two ended in previable loss. Thirty-six infants were born from 12 pregnancies of a mean gestational age of 33 weeks (28-38 weeks). The overall survival was 97.3%. Two women delivered vaginally. While the first was successful, the second resulted in vaginal delivery of the first two triplets followed by emergency CS for the third. That infant had a cord blood pH of 6.96 (BE-19), was resuscitated and survived. All 10 CS were successful. The mean cord blood gas tensions and pH were normal. In addition, Apgar scores, the requirement for mechanical ventilation or supplemental oxygen, and mortality did not differ between the first and third-born triplet. These observations suggest that CS was beneficial. Our very low mortality rate supports the concept that CS delivery and aggressive neonatal resuscitation and therapy greatly enhances survival.

Birth Order↗
PubMed1988

Human placental lactogen administration in the pregnant rat: acceleration of fetal growth.

To determine whether administration of human placental lactogen (hPL) to pregnant rats during late gestation might enhance fetal growth, we implanted osmotically driven minipumps to provide 75 micrograms h PL/24 h on day 14 of the rat's 21.5-day gestation. This substantially increased maternal and fetal plasma hPL concentrations. By day 18, hPL fetuses were significantly heavier and had larger placentas than controls. From this point until term, their rate of growth (1.20 g/24 h) significantly exceeded that of controls (0.95 g/24 h). Birth weights differed significantly (hPL 5.86 +/- 0.08 g; controls 5.20 +/- 0.08 g, p less than 0.001). This increase was due primarily to significant increases in the growth of the liver and carcass. Enhanced glucose availability was in part responsible for this phenomenon inasmuch as plasma glucose concentrations were significantly increased in hPL maternal rats from days 15 to 19. This resulted on days 18 and 19 in significantly increased plasma glucose and insulin concentrations in hPL fetuses. Fetal/maternal glucose ratios did not differ between hPL and control fetuses. Fetal heptic glycogen concentrations were significantly increased on day 18 and 19 but were similar to controls from day 20 until birth. These observations suggest that increased maternal glucose availability with consequent stimulation of fetal insulin secretion accelerated the growth of hPL fetuses. However, maternal and fetal plasma glucose concentrations and fetal plasma insulin and hepatic glycogen concentrations on days 20 and 21 were normal, suggesting that other factors also were responsible for sustaining the accelerated fetal growth on these days.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

3-O-methyldopa and the response to levodopa in Parkinson's disease.

Plasma 3-O-methyldopa (3OMD) concentrations in parkinsonian patients treated with levodopa on a long-term basis reflect daily levodopa dosage and do not vary markedly during the day. Oral challenges with 3OMD reduce the clinical response to levodopa infusions, but 3OMD is no more potent then phenylalanine in this regard. These observations, plus the fact that 3OMD makes a small contribution to the total concentration of large neutral amino acids competing with levodopa for transport at the blood-brain barrier, support the contention that 3OMD is not an important determinant of clinical response to levodopa.

Administration, Oral↗
PubMed1987

Tissue-specific expression of the RI and RII sodium channel subtypes.

Anti-peptide antibodies that distinguish between the rat brain sodium channel subtypes referred to as RI and RII were prepared and used to determine their relative expression in nerve and muscle tissues. Sodium channels purified from rat brain are approximately 18% RI and 80% RII. In brain, the RII subtype is preferentially expressed with RI/RII ratios ranging from 0.07 in the hippocampus to 0.17 in the cerebral cortex. The RI subtype is preferentially expressed in more caudal areas of the central nervous system with values of RI/RII of 0.98 for medulla oblongata and 2.2 for spinal cord. Expression of additional unidentified sodium channel subtype(s) is detected in midbrain, medulla, and spinal cord, and expression of unidentified sodium channel subtypes predominates over expression of RI and RII in retina and optic nerve. The RI and RII subtypes are primarily expressed in the central nervous system and are not detected in significant numbers in skeletal or cardiac muscle, sympathetic ganglia, adrenal medulla, sciatic nerve, or cauda equina. The RII subtype appears first in development of both brain and spinal cord but declines in adult spinal cord as the RI subtype increases. The strict regional expression of these two sodium channel subtypes suggests that they may have distinct functional properties or physiological roles.

Animals↗