Capillary hypertension and abnormal pressure dynamics in patients with essential hypertension

1. Pressure was measured within 28 capillaries of the nailfolds of nine patients with essential hypertension and in 33 capillaries of nine age- and sex-matched normotensive control subjects, using direct micropuncture, a dynamic servo-nulling system and computerized analysis. 2. Average pressure at the apex of the capillary was found to be elevated in the patients with hypertension (21.1 +/- 4.9 mmHg compared with 13.0 +/- 2.0 mmHg in the control subjects; mean +/- SD, P less than 0.01). If the two groups were combined, there was an overall correlation between average capillary pressure and mean blood pressure (r = 0.68, P less than 0.01, n = 18), but within each group separately there was no significant relation between these parameters. 3. There were also abnormalities in the waveforms of pulsations in capillary pressure in the group with hypertension, with an increased attenuation of high-frequency harmonics. Pulses appeared to be conducted more rapidly along the vascular tree in the patients with hypertension. 4. The elevation of capillary pressure in essential hypertension demonstrated in this study is in agreement with indirect evidence of capillary hyperfiltration provided by other studies which showed a reduced plasma volume and increased transcapillary escape rate of plasma proteins. 5. The finding of elevated capillary pressure demands the inclusion of the postcapillary segment (and possibly vascular density) in the resistance equation in essential hypertension.

A rapid DNA assay for the species-specific detection and quantification of Brugia in blood samples

This report describes a new assay for detecting filarial parasites of the genus Brugia in blood samples using labeled DNA probes. The sequences of these DNA probes are based on the HhaI repeat DNA family found in the genus Brugia. These DNA probes are species-specific and can detect the DNA from a single microfilaria in hybridization assays. To adapt this test for use on blood samples collected in the field, complex steps to separate microfilariae from blood cells and to purify parasite DNA were eliminated. We found that the most effective method was to filter blood samples through 5.0 microns pore nitrocellulose membranes, lyse the microfilariae on the membranes by proteinase K digestion, denature the parasite DNA with sodium hydroxide, and hybridize with the DNA probe. With this method, individual microfilariae can be visualized and counted on autoradiograms. The assay was evaluated in a mock field study using Brugia malayi-infected jirds and was found to be an efficient and accurate method for quantifying microfilariae in blood samples.

An evaluation of ketanserin therapy for the hypertensive diabetic patient

Hypertension may accelerate the development of the vascular complications of diabetes but many conventional antihypertensive agents have adverse effects on glucose tolerance or peripheral perfusion. To investigate the potential of ketanserin as an antihypertensive agent for hypertensive diabetics we performed a randomly allocated, double-blind, placebo-controlled trial in 17 patients. A range of peripheral blood flow responses was determined using laser Doppler flowmetry, and diabetic control was assessed at the time of allocation to groups and after 8 weeks' therapy (20 mg twice a day for 2 weeks; 40 mg twice a day for 6 weeks). The mean decrease in standing blood pressure was 14.1/9.3 mmHg (ketanserin treatment) versus 7.1/5.9 mmHg (placebo). The maximum skin blood flow and a posturally induced vasoconstriction of the foot skin were unaffected by the therapy, and glycaemic control was unchanged. Ketanserin was well tolerated. These studies suggest that ketanserin may be a useful agent for the treatment of hypertension in the diabetic patient.

Clinical television microscopy

The technique of television microscopy is the only available technique for the direct quantitative measurement of skin capillary blood flow. Television microscopy has applications in both research and clinical practice, and has attracted considerable interest from clinical groups attempting to study capillary blood flow. The critical requirements for a functioning system are difficult to ascertain from the published literature. The aim of this article is therefore to describe the individual components of a television microscope system, outline the current methods of analysis and briefly describe some of the clinical applications of television microscopy.

Human platelet glycoprotein IX: an adhesive prototype of leucine-rich glycoproteins with flank-center-flank structures

The glycoprotein (GP) Ib-IX complex on the surface of human platelets functions as the von Willebrand factor receptor and mediates von Willebrand factor-dependent platelet adhesion to blood vessels. GPIX is a relatively small (Mr, 17,000) protein that may provide for membrane insertion and orientation of the larger component of the complex, GPIb (Mr, 165,000). Using antibody screening, we cloned a cDNA encoding GPIX from a human erythroleukemia cell cDNA library constructed in phage lambda gt11. Lacking a 5' untranslated region and start codon, the cDNA sequence includes 604 nucleotides, beginning with 495 bases at the 5' end coding for 165 amino acids, followed by a stop codon and 106 noncoding bases at the 3' end. By Northern blot analysis, the GPIX cDNA hybridizes with a single 1.0-kilobase species of platelet poly(A)+ RNA. Translation of the cDNA sequence gives a predicted protein sequence beginning with a truncated putative signal sequence of 5 amino acid followed by a sequence of 17 amino acids matching that determined directly by Edman degradation of intact GPIX. The predicted amino acid sequence of mature GPIX includes an NH2-terminal extracytoplasmic domain of 134 residues, a transmembrane domain of 20 residues, 6 intracytoplasmic residues, and 1 N-linked glycosylation site. GPIX contains a leucine-rich glycoprotein (LRG) sequence of 24 amino acids similar to conserved LRG sequences in GPIb and other proteins from humans, Drosophila, and yeast. "Flanking" sequences of approximately 22 amino acids are present at the NH2 and/or COOH sides of the "central" LRG sequence(s) in GPIX, GPIb, and the other human and Drosophila members of the LRG family. The role of the flank-LRG center-flank structure in the evolution and function of the LRG proteins remains to be defined.

An assessment of dental caries prevalence among Gujurati, Pakistani and white Caucasian five-year-old children resident in Dewsbury, West Yorkshire

A number of recent studies have reported higher levels of caries experience in the primary dentition of Asian when compared with white Caucasian children. However, in order to take account of the diversity of socio-cultural and religious backgrounds, an Asian 'sample' should be specified. The present study examined caries prevalence among three distinct groups of five-year-old children, Pakistani Muslim, Indian Gujurati Muslim and white Caucasian. All were resident in districts of urban deprivation in Dewsbury. Significantly more of the 200 white Caucasian children examined were found to be caries-free (50 per cent) compared with 35 per cent of the Pakistani (n = 242) and 31 per cent of the Indian group (n = 159). Extensive caries was seen far more frequently in the Asians. Only 5 per cent of the white Caucasian children had rampant caries (dmft less than/= 10), but 13 per cent of the Pakistani and 21 per cent of the Indian group were so affected. Mean caries prevalence values were also higher among the Asian children. There was little difference in the levels of disease between the two Asian groups, except for rampant caries, which was higher among Indian children. All groups had more teeth decayed than treated. However, the white Caucasian girls had the lowest mean values of caries experience and the highest proportion of f/m teeth, indicating the most favourable level of restorative care. There was extensive untreated disease in all the Asian groups. The findings show that improved prevention and treatment facilities are required for young children, especially those from these Asian communities. Health education programmes and treatment facilities must be culturally acceptable and accessible. Both developments could be co-ordinated by the community dental service, the treatment facility most frequently used by these Asian communities at present.

A statistical test that supports a human/chimpanzee clade based on noncoding DNA sequence data

Using the aligned DNA sequence data of Miyamoto et al. and Maeda et al., all noncoding genetic material, and a simple statistical test, we show that a Homo/Pan clade is supported at approximately the 3% level of significance. The method accommodates polymorphism and different evolutionary rates for different sites. All assumptions on which the statistical study is based are made explicit. (See the Note added in proof, which--adding recently published data--improves the significance level to about 1%.

Dentists and ethnic minority communities

It is estimated that 4.5% of the UK population originates from the New Commonwealth and Pakistan (NCWP). However, the distribution is not equal. For instance, two-thirds of all young children in the inner wards of Birmingham, and one-third of those in inner London, have parents who were born in the NCWP. Uptake of dental services is reported to be low in some inner city areas. There, as elsewhere, dental care needs to be accessible, acceptable and appropriate. But how are these objectives best achieved?

Dependent oedema and attenuation of postural vasoconstriction associated with nifedipine therapy for hypertension in diabetic patients

We studied the incidence of oedema 2 weeks following initiation of nifedipine therapy for hypertension in a group of 10 diabetic subjects, and also measured skin blood flow (SBF) with a laser Doppler flowmeter, before and after lowering the foot. SBF with the foot horizontal increased after nifedipine from 0.31 V (arbitrary units of flow) to 0.51 V (NS). The postural fall in blood flow in dependency was significantly attenuated by nifedipine from 64.4 to 24.0%. Five patients developed ankle oedema. Results were similar in a small group of non-diabetic subjects starting nifedipine. The attenuation of reflex postural vasoconstriction is therefore likely to contribute to development of the oedema associated with starting nifedipine therapy, which should be monitored carefully in diabetic patients.

The rat facilitated glucose transporter gene. Transformation and serum-stimulated transcription initiate from identical sites

The gene encoding the rat brain facilitated glucose transporter protein was cloned and partially sequenced. The transcribed regions encode 10 exons that span about 30 kilobases of genomic DNA. The intron size is markedly biased, the first two significantly greater in length than the seven others. All of the introns are predicted to occur in regions that encode putative extramembranous domains of the protein, consistent with the proposed topology of 12 alpha-helical membrane-spanning segments. In brain, transcription of the glucose transporter gene initiates at two adjacent adenosine residues located about 30 base pairs 3' to a TATA sequence. In addition, there is at least one minor upstream start site. Both transformation of fibroblasts by the oncogenic retrovirus Fujinami sarcoma virus and stimulation of quiescent fibroblasts with serum increase transcription of the glucose transporter gene from identical initiation sites, which are the same as the predominant start sites in brain. The use of the same promoter for increased transcription under both conditions is consistent with the hypothesis that the regulation of gene expression by normal growth and by oncogenesis is mediated by similar or identical pathways.

Isolation and characterization of human platelet glycoprotein IX

Human platelet glycoprotein IX is a small (Mr 17,000) surface glycoprotein present in the plasma membrane as a 1:1 non-covalent complex with glycoprotein Ib (Mr 165,000). Glycoprotein IX was purified to near homogeneity by sequential wheat germ agglutinin and immuno-affinity chromatography, followed by gel filtration chromatography under denaturing conditions. Purified glycoprotein IX was characterized by determination of its amino acid composition and its NH2-terminal amino acid sequence (thr-lys-asp-xxx-pro-ser-xxx-leu-thr-(thr)2-arg-ala-(leu)-(glu)-xxx-met- gly), and monospecific anti-glycoprotein IX antibody was prepared. The study outlines a useful approach for separating and characterizing glycoprotein IX, free from other members of the glycoprotein Ib complex.

Dynamic measurement of human capillary blood pressure

1. Capillary blood pressure was measured in man using a dynamic servo-nulling system and direct micropuncture. This enabled assessments of the normal variations in pressure which influence fluid filtration and reabsorption. 2. Seventy-eight capillaries in 19 subjects were punctured in one of three positions around the capillary loop with the hand at the level of the sternal angle. Mean pressure around the loop fell from 37.7 +/- 3.7 mmHg (arteriolar limb, mean +/- SEM, n = 12) to 19.4 +/- 1.0 mmHg (apex, n = 25) to 14.6 +/- 0.5 mmHg (venular limb, n = 41) at skin temperatures of 18.7-33.1 degrees C. These values agree closely with Landis' original studies in 1930 [E. Landis (1930) Heart, 15, 209-228]. 3. The mean filtration/reabsorption state of any particular capillary limb was not static because of cardiac, vasomotor and respiratory fluctuations in capillary pressure. From a total of 38 capillaries in which recordings were analysed for 30 s, the fluctuations in pressure were such that 27 capillaries probably had periods of both filtration and reabsorption. 4. Computerized superimposition and coherent averaging of trains of capillary pulses enabled an accurate description of the pulse waveform to be made in three capillaries. This was remarkably similar to waveforms from the radial artery, albeit at reduced amplitude (average 3.6 +/- 3.4 mmHg, mean +/- SD overall). The time for the pulse to travel between the radial artery and the finger capillary was approximately 10 ms, which implies a propagation velocity of several metres per second.(ABSTRACT TRUNCATED AT 250 WORDS)

Species-specific oligonucleotide probes for the identification of human filarial parasites

Species-specific oligonucleotide probes have been constructed for the filarial parasites Brugia malayi and Brugia pahangi. Both parasites contain a 322 base pair repeated DNA sequence that is cleaved once by the restriction endonuclease HhaI. A consensus repeat sequence was determined from the DNA sequence of 15 cloned isolates of each species. Although the two repeats have an average homology of 89%, half the differences are clustered in a region of 66 nucleotides that has a homology of only 72%. Within this region, two probes, a 29-mer that is B. malayi specific and a 21-mer that is B. pahangi specific, were constructed. The sequence of both probes was chosen to obtain the maximum difference between the consensus sequences of the two species. The probes were also selected to be GC rich to increase their stability as a DNA hybrid. In a filter hybridization assay, the B. malayi probe has a 500-fold preference for B. malayi DNA versus B. pahangi DNA and a sensitivity of 200 pg. The B. pahangi probe has similar specificity and sensitivity for B. pahangi DNA. A rapid lysis procedure allows the probes to detect 1-2 third stage larvae of either B. malayi or B. pahangi in a filter hybridization assay.

Isolation and characterization of the receptor on human neutrophils that mediates cellular adherence

The receptor on human neutrophils (polymorphonuclear leukocytes or PMN) that mediates cellular adherence has been purified from the peripheral blood PMN obtained from an individual with chronic myelogenous leukemia (CML). This receptor consists of two noncovalently associated subunits, designated alpha M (Mac-1 alpha, CD11b) (Mr = 170,000) and beta (Mac-1 beta, CDw18) (Mr = 100,000), respectively, which are identical on normal and CML PMN. The subunits were purified by monoclonal antibody 60.1-Sepharose (anti-alpha M) affinity chromatography and separated in 5-nmol quantities by high pressure liquid chromatography on a TSK-4000 gel filtration column. Subunits were characterized by amino acid composition, NH2-terminal amino acid sequence, and carbohydrate content. The NH2-terminal sequence of the human PMN alpha M subunit contains regions of homology with the human platelet glycoprotein IIb alpha. We conclude that nanomole amounts of individual alpha M and beta subunits of the receptor on human PMN that mediates cellular adherence can be isolated and separated using CML PMN.

Capillary blood pressure

Human capillary blood pressure may be measured directly in nailfold capillaries of the fingers and toes. By applying servonulling pressure measuring techniques rapid fluctuations in capillary pressure may be recorded, opening the way to a greater understanding of capillary pressure control in health and disease. The estimation of mean pressure which may be accomplished manometrically is of value in determining the mechanism of oedema, identifying the site of raised peripheral resistance in disease states, evaluating the effects of vasoactive drugs on peripheral resistance, and investigating haemodynamic abnormalities associated with microangiopathies. Capillary pulse waveform analysis, made possible by servonulling techniques and computer analysis has already revealed important changes in hypertension.

Synthesis and NMR spectra of 13C-labeled coenzyme A esters

The synthesis of coenzyme A thioesters of 13C-labeled acetate, propionate, succinate, and methyl malonate is described. The average yields were 94%. The 13C-NMR spectra were determined to provide a reference for the resonance positions of these metabolites. The synthesis of coenzyme thioesters of small-molecular-weight acids labeled with 13C has not been described previously, nor have the resonance positions been previously reported.

Impaired microvascular hyperaemic response to minor skin trauma in type I diabetes

The microvascular response of foot skin to minor thermal injury and the skin of the anterior abdominal wall to injury from a needle was assessed by laser Doppler flowmetry in 23 patients with type I diabetes and 21 healthy control subjects. After minor thermal injury mean (SD) maximum skin blood flow was significantly lower in the diabetic group than the control group (0.53 (0.11) v 0.72 (0.10) V, in arbitrary units of flow, respectively, p less than 0.001) and was negatively correlated with the duration of diabetes (r = -0.60; p less than 0.01). After needle injury a similar pattern of impairment was seen, the peak flow value recorded being significantly lower in the diabetic group than the control group (0.28 (0.10) v 0.41 (0.09) V, respectively; p less than 0.001) and also negatively correlated with the duration of diabetes (r = -0.61; p less than 0.01). There was a significant relation between the response obtained at the two sites of injury in the diabetic group (r = +0.72, p less than 0.001) but not in the control group. The impairment in response was not related to diabetic control and was not explicable in terms of a reduction in superficial skin capillary density. The inability of the diabetic skin microvasculature to respond normally to injury may be an important factor in the development of foot ulceration that often follows minor trauma.

Cloning and comparison of repeated DNA sequences from the human filarial parasite Brugia malayi and the animal parasite Brugia pahangi

A 320-base-pair repeated sequence was observed when DNA samples from the filarial parasites Brugia malayi and Brugia pahangi were digested with the restriction endonuclease Hha I. A 640-base-pair dimer of the repeated sequence from B. malayi was inserted into the plasmid pBR322. When dot hybridization was used, the copy number of the repeat in B. malayi was found to be about 30,000. The 320-base-pair Hha I repeated sequences are arranged in direct tandem arrays and comprise about 12% of the genome. B. pahangi has a related repeated sequence that cross-hybridizes with the cloned B. malayi Hha I repeat. Dot hybridization with the cloned repeat shows that the sequence is present in B. malayi and in B. pahangi but not in four other species of filarial parasites. The cloned repeated DNA sequence is an extremely sensitive probe for detection of Brugia in blood samples. Hybridization with the cloned repeat permits the detection of DNA isolated from a single parasite in an aliquot of blood from animals infected with B. malayi. There are differences in the restriction sites present in the repeated sequences that can be used to differentiate between the two Brugia species. The B. malayi repeated DNA sequence is cleaved by Alu I and Rsa I but the B. pahangi sequence is not. A comparison of repeated sequences between the two species by DNA sequence analysis indicates that some regions of individual repeats are over 95% homologous, while other short regions are only 60-65% homologous. These differences in DNA sequence will allow the construction of species-specific hybridization probes.