Use of questionnaire screening for vibration white finger in a high risk industrial population.

OBJECTIVES: To compare the results of questionnaire screening with those of objective testing in the identification of vibration white finger (VWF) in a high risk population. METHODS: Three groups of men (79 riveters, 52 healthy controls and 79 compensation claimants) were assessed for VWF by a detailed questionnaire covering occupational and general medical history and incorporating specific questions related to the presence or absence of relevant symptoms in their hands. Each then underwent provocative cold testing under controlled conditions using established protocols. The presence or absence of digital vasospasm following cooling was determined by finger systolic pressure measurements using laser Doppler flowmetry. The test protocols used have been evaluated in patients with a clear clinical diagnosis of non-occupational Raynaud's syndrome. RESULTS: 6.3% of the riveters and 83.5% of the claimants reported specific Raynaud's syndrome symptoms but 30.4% of the riveters and only 19% of the claimants tested positive for vasospasm after middle phalangeal cooling to 10 degrees C for 5 min. Using a more severe cooling protocol provoked vasospasm in 46.8% of the claimants. Lack of sensitivity or specificity of the objective testing could not explain the large discrepancies between the findings in the riveters and in the claimants. CONCLUSIONS: Questionnaire responses concerning VWF symptoms can be influenced by the context in which they are recorded. It is important to employ more objective methods in assessing all workers at risk of developing VWF.

Acute effects of vibration on peripheral blood flow in healthy subjects.

OBJECTIVES: The main objective was to study the acute vascular effects in the hands of normal healthy subjects of a complex vibration spectrum similar to that generated by many industrial hand held tools. The effects of repeated bouts of vibrations and alterations in the intensity of vibration were also studied. METHODS: Blood flow was measured by venous occlusion plethysmography with strain gauges. Vibration across a frequency range of 0.4 to > 4000 Hz was generated by a pneumatic chisel and applied to the right hand. Blood flow was measured in both middle fingers, both big toes, or both forearms before, during, and after a two minute period of vibration. Systolic pressure of a finger and heart rate were also measured. RESULTS: Vibration was associated with a significant bilateral reduction in finger and toe blood flow (P < 0.01 and P < 0.03) and a significant increase in heart rate (P < 0.05) but had no effect on forearm blood flow. The finger response was not abolished by repeated bouts of the vibration but was initially most notable during the first minute of vibration. Increasing the intensity of vibration delayed recovery. CONCLUSIONS: Hand vibration causes a generalised increase in sympathetic tone in the heart and extremities. This may be a factor in the development of vasospastic disease in habitual users of hand held industrial vibrating tools.

Small or absent fetal stomach: prognostic significance.

PURPOSE: To investigate the outcome of fetuses with a small or absent stomach. MATERIALS AND METHODS: We retrospectively reviewed sonograms in 87 fetuses with a small or absent stomach. Gestational age, amniotic fluid volume, stomach size, morphologic defects, and karyotypes were correlated with clinical follow-up or autopsy findings. RESULTS: Eight pregnancies were excluded because of oligohydramnios due to ruptured membranes. Seventy-nine fetuses with an absent (n = 27) or small (n = 52) stomach were included in the study group. Gestational ages ranged from 18 to 39 weeks (mean, 27 weeks). An abnormal outcome (structural abnormalities, intrauterine fetal or postnatal death) occurred in 23 (85%) of 27 fetuses with an absent stomach and 27 (52%) of 52 fetuses with a small stomach (combined, 63%). Karyotype was abnormal in eight (38%) of 21 fetuses with an absent stomach and two (4%) of 46 fetuses with a small stomach. CONCLUSION: An absent or small fetal stomach after 18 weeks gestation is associated with a guarded prognosis.

Prenatal diagnosis of esophageal atresia.

The prenatal sonographic detection of esophageal atresia (EA) has been possible for more than a decade and relies on the finding of a small or absent fetal stomach bubble associated with maternal polyhydramnios. The aims of this study were to assess the accuracy of this technique and to determine whether the outcome of prenatally diagnosed EA differs from its postnatal counterpart. All fetal sonograms performed between January 1989 and October 1993 demonstrating a small or absent fetal gastric bubble were reviewed together with all neonates with EA treated during the same period. Eighty-seven fetuses with a small (n = 53) or absent stomach bubble (n = 34) were identified, representing 1.4% of all fetal sonographic surveys. Esophageal atresia was present in 15; in 13 of these, the maternal amniotic fluid volume was increased. The positive predictive value of an absent stomach bubble and polyhydramnios was 56%, and the sensitivity of prenatal sonography in the diagnosis of EA was 42%. One neonate with EA had the prenatal diagnosis established at another institution, yielding a total of 16 cases of prenatally diagnosed EA for analysis. Seven (44%) of these had trisomy 18. Of the remaining nine, two had isolated EA, two had laryngeal atresia and EA, and there were two late-gestational unexplained fetal deaths. Only four (25%) survived through the neonatal period. The prognosis of the fetus with EA is radically different from that of the neonate with EA.

The empty amnion: a sign of early pregnancy failure.

Between 6.5 to 10 weeks of gestation, the length of the amniotic cavity is similar to that of the embryo. It follows that by the time an amniotic sac is detectable sonographically, an embryo of equal length should also be visualized. Retrospective review of case records at our institution revealed 15 patients in whom the amnion was visualized in the absence of an embryonic pole during first trimester sonography (endovaginal and transvesical). Indications for sonographic examination included gestational age estimation, discrepant size and dates, or vaginal bleeding. The mean sac diameter for the 15 gestations ranged from 14 to 36 mm, corresponding to gestational ages of 6.1 to 9.5 weeks. Ages based on the last menstrual period ranged from 6.1 to 11 weeks. A yolk sac was identified in all cases in addition to the amniotic sac, but neither an embryo nor cardiac pulsations were observed. In 12 of the 15 cases the size of the gestational sac was greater than 16 mm, such that the absence of an embryo also met an accepted criterion for a failed pregnancy. Follow-up in all cases confirmed early pregnancy failure. In this series the demonstration of an "empty amnion" (visualization of an amnion but no identifiable embryonic pole) was always associated with pregnancy loss. The "empty amnion" sign is helpful as an additional finding confirming early pregnancy failure.

Vascular responses in chain saw operators.

The intensive use of chain saws is associated with development of the hand-arm vibration syndrome (vibration white finger). Objective testing for cold induced vasospasm was carried out on the fingers of 12 chain saw operators and 12 matched control men from a similar working environment. Two of the chain saw operators tested positive for vasospasm in the laboratory and another three had an abnormal result. All of the control subjects tested negative. Measurements of finger blood flow at different temperatures and during vibration of the hand were similar in the chain saw operators and controls. Use of the chain saw did not cause significant alterations in the plasma concentrations of von Willebrand factor antigen in either the long or the short term.

An investigation into the acute vascular effects of riveting.

Measurements were made on 46 pairs of riveters and matched control subjects before and after a morning's work. Before starting work, the mean resting finger systolic pressure was 112 (SEM 3.3) mm Hg in the riveters, similar to 117 (1.7) in the control subjects. After cooling the middle phalanx to 10 degrees C for five minutes, 16 riveters but only one control subject exhibited digital vasospasm and these numbers were unaltered after a morning's work. A subgroup of riveters whose role was always to provide counter pressure to the rivet gun showed a higher incidence (45%) of cold induced vasospasm than did riveters who invariably held the gun (10%) or rotated between both roles (27%). Plasma levels of three markers of vascular activity, endothelin-1 (ET-1), von Willebrand factor antigen (vWFAg), and angiotensin converting enzyme (ACE), were measured in non-smoking riveters and control subjects. Before work, ET-1 concentrations were slightly lower (p < 0.05) in the riveters, but vWFAg concentration and ACE activity were similar in riveters and control subjects. Riveting for a morning did not alter ET-1 concentration or ACE activity but did induce a small increase (p < 0.05) in vWFAg concentration, which may indicate damage to the endothelium. This type of vascular assessment may be helpful in assessing vasospastic complications in workers exposed to vibration.

Magnetic resonance imaging of the tongue and oropharynx.

In general, MRI produces superior soft tissue detail in evaluating the tongue and oropharynx than does CT. MRI is therefore considered the study of choice in this area. Lack of artifact from dental amalgam and beam hardening artifact from the mandible on MRI also eliminates two major shortcomings of CT in the examination of this area. Finally, the ability of MRI to obtain direct coronal and sagittal scan planes is a distinct advantage in recognizing intrinsic tongue musculature and assessing tumor volume and spread for treatment planning.

Hirsutism in a gynaecological context.

Investigation of patients presenting with hirsutism to a gynaecological endocrine clinic revealed a high incidence of anovulation, obesity and elevated androgen levels. The underlying abnormality was polycystic ovarian syndrome (PCOS) in the majority of patients. Low levels of sex hormone binding globulin were common; these increased with oestrogen treatment. Treatment with a combined oral contraceptive pill and low dose spironolactone was often effective in reducing symptoms.

Combined treatment with gonadotrophin releasing hormone agonist and gonadotrophins in poor responders to hyperstimulation for in vitro fertilization (IVF): clinical and endocrine results.

Seventy three cycles of combined gonadotrophin releasing hormone (GnRH) agonist/gonadotrophin treatment for IVF controlled ovarian hyperstimulation in previous poor responders to standard ovarian hyperstimulation therapy are reported. Oocyte numbers obtained were better than the previous average results, but were similar to the previous best response. In general more oocytes than the previous mean could be expected but low order responders were not transformed into high order responders. Pregnancies did occur in this difficult group of patients but the rate was modest. Because of a reduction in cancelled cycles, patients might reduce their total costs in time and gonadotrophin used, however this treatment is not a panacea for the true low order responder.

Clomiphene citrate and ovarian resistance.

An uncommon association between clomiphene citrate and the development of ovarian resistance to gonadotrophins is described. We advise against the use of clomiphene in the rare patient with the resistant ovary syndrome, and advise caution in any patient who exhibits a decreasing oestrogen response to clomiphene ovulation induction.

The fate of supernumerary oocytes in gamete intrafallopian transfer (GIFT) is not predictive of a poor outcome: the effect of oocyte selection.

In 161 consecutive gamete intrafallopian transfer (GIFT) cycles in which supernumerary oocytes were inseminated, a failure to fertilize any of these oocytes was no more predictive of an unsuccessful outcome than the simple overall pregnancy rate in this group. This is possibly related to the significantly reduced proportion of oocytes graded as good in the supernumerary group.

Anti-oestrogens: their clinical physiology and use in reproductive medicine.

The anti-oestrogens are important both as therapeutic agents in reproductive medicine and as tools to investigate the physiology of the oestrogen receptor and hormonal control mechanisms. Clomiphene occupies the oestradiol receptor and, although initially stimulatory, has a net antagonistic effect as oestrogen receptors are not replenished. The major fertility-enhancing effect is to cause an increase in LH and FSH output by increasing the frequency of pulsatile output of these hormones. Many effects due to an anti-oestrogenic effect have been postulated; some, such as an adverse effect on cervical mucus, have been proven. The clinical use of the anti-oestrogens is outlined in Table 1. In well chosen patients a rewarding pregnancy rate is obtained with minimal intervention and few important side-effects. The challenge for the reproductive biologist is successfully to manage the patient who is clomiphene-resistant, either because of failure to ovulate or failure to conceive once ovulation is induced.

Approaches to MR angiography.

One of the most revolutionary recent imaging advances is the use of magnetic resonance to study and produce morphologic representations of flowing blood vessels known as MR angiography. The ability to produce an image of even moderate spatial resolution of the three dimensional course of blood vessels with MR could have significant advantages over conventional invasive angiography which requires ionizing radiation and contrast material injection. By definition, MR angiography does not require the addition of any intravascular contrast agents and the images are produced entirely by the effect of the radio frequency pulses and magnetic field gradients on the spinning protons. Several researchers are already producing relatively high resolution MR angiograms using a variety of techniques. Essentially all techniques of MR angiography use variations of three steps to produce the image: (1) a projection image, (2) suppression of background static material, and (3) production of a flow sensitive image. This report will survey some of the more commonly used approaches to MR angiography that are currently under investigation.