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PubMed1996

[Bertha Röntgen or the transparency of the hand].

It is to Wilhelm Conrad Röntgen, the first elected "radiologist" of our Academy and the first Nobel Prize winner in physics, that we owe the transparency of the hand. We celebrate today the centenary of the great scientific discovery which was to revolutionize the diagnosis, and thereby the treatment, of a large number of illnesses the discovery of X-rays. It would be unjust not to link the name of this scientist with that of his wife, Bertha, who, ignorant of the dangers of all "novel medical inventions" volunteered her own hand for his research experiments: the hand which was to bring to the world tangible proof of this remarkable discovery. To a lesser degree, but nonetheless essential, we acknowledge, albeit not in exhaustive detail, all the progress made by the work of pioneers using this new investigative technique. So let us now return to the hand:--a body part which it was easy to immobilize, remembering that in those days a single radiographic exposure took up to an hour to obtain,--we will consider the immortalised hand of Bertha Röntgen,---to whom this address is dedicated,---and its radiographic exposures which allow us to appreciate the advances and to perceive the limitations of this technique. They also enable us better to envisage future investigative approaches whereby a deeper knowledge of the human body may be acquired. We note that compared with the histopathological sciences, imaging is not specific. Numerous microscopic structures, in particular neurological and vascular ones, are still insufficiently well visualised and the transmission pathways between the hand and the central nervous system deserve better characterisation. Current, research programmes are attempting to overcome these limitation of modern imaging. All the experience gained in studying the transparency of the hand, as we have discussed, is applicable to every part of the human anatomy. To credit: Röntgen's discovery with all its originality, we could say that the hand was to radiology what the brain was to CT and MRI scanning: an exceptional victory is rendering the human body transparent.

Female↗

PubMed1998

Cerebrally lateralized mental representations of hand shape and movement.

Previous psychophysical and neuroimaging studies suggest that perceiving the handedness of a visually presented hand depends on sensorimotor processes that are specific to the limb of the stimulus and that may be controlled by the cerebral hemisphere contralateral to the limb. Therefore, it was hypothesized that disconnection between cerebral hemispheres would disrupt mental simulation of a hand presented to the ipsilateral, but not the contralateral, hemisphere. This hypothesis was examined by the present study in which two callosotomy patients and eight healthy controls judged the handedness of drawings of left and right hands in various positions, without moving or inspecting their own hands. Stimuli were presented for 150 msec in the right or left visual hemifield. As predicted, for each hemisphere, patients' accuracy was high when the hand was contralateral to the perceiving hemisphere, but it was not above chance when it was ipsilateral to the perceiving hemisphere. Controls' accuracy was high in both conditions. Response time analyses indicate patients, like controls, mentally simulated reaching into stimulus postures. When the stimulus laterality was ipsilateral to the perceiving hemisphere, patients imagined the hand contralateral to the perceiving hemisphere reaching into the stimulus posture but did not detect the mismatch, guessing with a response bias or responding on the basis of shape similarity. We conclude that each hemisphere could represent the shape and movement of the contralateral hand but could not for the ipsilateral hand. Mentally simulating one's action and discriminating body part handedness both depend on lateralized sensorimotor and somatosensory representations.

Adult↗

PubMed2002

Concerns about human hand transplantation in the 21st century.

The decision to perform a human hand transplant was justified perhaps on less than an ideal scientific basis-only approximately 60 rat limb transplants and 2 primate limb transplants have survived for longer than 200 days and only 8 of 19 pig limb osteomyocutaneous transplants showed no signs of rejection at 90 days. It seems unlikely that the survival of a human hand transplant will be any better than the survival of a kidney transplant, which has a half-life of approximately 7.5 to 9.5 years. Fourteen hand transplants, however, have now been performed in 11 humans with the skin component of 1 remaining viable up to 3 years after surgery. Intermittent episodes of acute rejection seem to have been relatively simple to reverse by temporarily increasing the dose of immunosuppressive agents and steroids. Chronic rejection has occurred in 1 patient, necessitating re-amputation of the transplanted hand. Active range of motion of the digits has been surprisingly better than would have been expected based on previous results of replantation, but return of sensibility has been less than optimal. The immunosuppression has been well tolerated without any major medical problems or life-threatening episodes, but some patients have developed chronic viral and fungal infections and several have developed posttransplant diabetes. Extrapolating from the previous experience of solid-organ transplants, chronic immunosuppression may predispose a hand transplant patient to an 80% chance of developing an infection, a 20% potential risk of developing posttransplant diabetes, and a 4% to 18% potential risk of developing a malignancy. Even though there is universal agreement that composite tissue allograft transplantation will become the ultimate reconstructive option, no one can predict the eventual role of hand transplantation in the future, but perhaps an international database of these hand transplant patients should be established so that independent reviewers can more objectively evaluate their functional outcome, the incidence of chronic rejection, and the risks of long-term immunosuppression.

Amputation, Traumatic↗

PubMed1995

A descriptive study of health problems on car mechanics' hands.

The purpose of the present study was to investigate occupational health problems relating to the hands of car mechanics. A descriptive study was performed among all car mechanics in 22 car repair shops using a self-administered questionnaire. In total, 172 car mechanics returned the questionnaire (92%). Fourteen per cent reported occurrence of white fingers, 24% reported occurrence of paresthesias in hands or arms, 41% reported that dry skin on their hands was often a problem, 46% reported occurrence of hand eczema, and 28% had experienced more than 20 cuts on the hands in the past year. A significant relationship was found between the occurrence of hand eczema and employment for less than 14 years as a car mechanic. This was also found for occurrence of white fingers and cuts on the hands. Further surveillance of the working environment among car mechanics seems to be required.

Automobiles↗

PubMed1999

Diversity of conformational states and changes within the EF-hand protein superfamily.

The EF-hand motif, which assumes a helix-loop-helix structure normally responsible for Ca2+ binding, is found in a large number of functionally diverse Ca2+ binding proteins collectively known as the EF-hand protein superfamily. In many superfamily members, Ca2+ binding induces a conformational change in the EF-hand motif, leading to the activation or inactivation of target proteins. In calmodulin and troponin C, this is described as a change from the closed conformational state in the absence of Ca2+ to the open conformational state in its presence. It is now clear from structures of other EF-hand proteins that this "closed-to-open" conformational transition is not the sole model for EF-hand protein structural response to Ca2+. More complex modes of conformational change are observed in EF-hand proteins that interact with a covalently attached acyl group (e.g., recoverin) and in those that dimerize (e.g., S100B, calpain). In fact, EF-hand proteins display a multitude of unique conformational states, together constituting a conformational continuum. Using a quantitative 3D approach termed vector geometry mapping (VGM), we discuss this tertiary structural diversity of EF-hand proteins and its correlation with target recognition.

Amino Acid Motifs↗

PubMed1998

Effects of upright posture on hand preference for reaching vs. the use of probing tools by tufted capuchins (Cebus apella).

This research examined the effects of task (reaching vs. tool use) and posture (quadrupedal vs. bipedal) on hand preference in tufted capuchins (Cebus apella). Regarding direction of hand preference, we found a significant main effect of posture, as the bipedal stance elicited greater use of the right hand than did the quadrupedal stance, and a significant posture x task interaction, as bipedal reaching elicited greater use of the right hand than did other postural and task conditions. Further, we found a significant main effect of task on strength of hand preference, as tool use elicited more consistent use of one hand over the other than did reaching. Our findings indicate that bipedal reaching facilitates a mild right-hand bias in intensely manipulative primates. We speculate that this moderate bias may have been pushed in the direction of nearly exclusive right-hand preference in most humans with the development of complex tool use.

Animals↗

PubMed2005

Hands and knees posture in late pregnancy or labour for fetal malposition (lateral or posterior).

BACKGROUND: Lateral and posterior position of the baby's head (the back of the baby's head facing to the side or the mother's back) may be associated with more painful, prolonged or obstructed labour and difficult delivery. It is possible that certain positions adopted by the mother may influence the baby's position. OBJECTIVES: The objective of this review is to assess the effects of adopting a hands and knees maternal posture in late pregnancy or during labour when the presenting part of the fetus is in a lateral or posterior position, compared with no intervention. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group Trials Register (November 2004) and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 4, 2004). SELECTION CRITERIA: Randomised trials of hands and knees maternal posture compared to other postures or controls. DATA COLLECTION AND ANALYSIS: Both review authors assessed trial eligibility and quality. MAIN RESULTS: Two trials of hands and knees posture during pregnancy were included. In one trial involving 100 women, four different postures (four groups of 20 women) were combined for the comparison with the control group of 20 women. Lateral or posterior position of the presenting part of the fetus was less likely to persist following 10 minutes in the hands and knees position compared to a sitting position (one trial, 100 women, relative risk (RR) 0.25, 95% confidence interval (CI) 0.17 to 0.37). In a second trial including 2547 women, advice to assume the hands and knees posture for 10 minutes twice daily in the last weeks of pregnancy had no effect on the baby's position at delivery or any of the other pregnancy outcomes measured. No trials of hands and knees posture during labour were included. AUTHORS' CONCLUSIONS: Use of hands and knees position for 10 minutes twice daily to correct occipitoposterior position of the fetus in late pregnancy cannot be recommended as an intervention. This is not to suggest that women should not adopt this position if they find it comfortable. The use of this position during labour has not been addressed in this review. In view of the promising short-term effects of the technique and its simplicity, further trials are justified to determine whether encouraging the use of hands and knees posture during rather than before labour, has any effect on substantive outcomes.

Delivery, Obstetric↗

PubMed2003

Weight from birth to 53 years: a longitudinal study of the influence on clinical hand osteoarthritis.

OBJECTIVE: To determine the influence of body weight throughout the life course on the development of clinical hand osteoarthritis (OA). METHODS: A British national survey was used to perform a prospective cohort study of 1,467 men and 1,519 women born in 1946. Weight was measured at birth and at subsequent followup visits through childhood and adulthood. The main outcome measure was the odds ratio for the presence of hand OA at the age of 53 years. RESULTS: Two hundred eighty men (19%) and 458 women (30%) had OA in at least 1 hand joint. Hand OA was significantly associated with increased weight at ages 26 years, 43 years, and 53 years and with decreased weight at birth in men. Birth weight and adult weight showed independent effects, such that men with the highest risk for OA represented those who had been heaviest at age 53 years and lightest at birth. These findings were not explained by grip strength. There was no significant relationship between weight and hand OA in women. CONCLUSION: The results of this study show that increased adult weight is associated with, and may precede, development of hand OA in men. An association between hand OA and weight was not observed in women. The relationship between hand OA and decreased birth weight is a new finding and may reflect the persisting influence of prenatal environmental factors on adult joint structure and function.

Adolescent↗

PubMed1993

Haptic discrimination of nonsense shapes: hand exploratory strategies but not accuracy reveal laterality effects.

Studies on haptic processing show inconsistent results concerning sex and hand differences. We present a novel approach in which manual exploratory strategies were examined. Twenty-four right-handed adults of both sexes had to monohaptically explore unseen meaningless stimuli and then to recognize their visually presented outline drawings among drawings of different stimuli. Tactual stimuli were composed of eight smoothly joined cubes whose junctions were not haptically discernible. The computer recorded number and duration of hand contacts on each cube. Analyses included the accuracy of the recognition phase, the number and duration of exhaustive explorations of the stimulus, and the number of cubes simultaneously touched. Neither hand nor sex differences were found for the accuracy measurement. The number and duration of exhaustive explorations also provide no evidence of hand differences. However, the left hand touched simultaneously more cubes than the right and this asymmetry was more pronounced in males than in females. Such an asymmetry was apparent in the very first contact of the hand with the shape. It is suggested that exploratory strategies may be more sensitive measures in revealing hand lateralization than the accuracy measurement.

Adult↗

PubMed1986

Heat-induced vasoconstriction in the fingers: a mechanism for reducing heat gain through the hand heated locally.

This study examined the effect of local heating on the blood flow of the finger or forearm in male subjects in an environment of 35 degrees C--40% (r.h.). One hand or forearm was immersed in a water bath the temperature of which (Tw) was raised by 1 degrees C every 10th min from 35 degrees to 43 degrees C, while the other hand or forearm was kept at a constant Tw of 35 degrees C. Blood-flow (BF) was measured by venous occlusion plethysmography, using temperature-compensated mercury-in-Silastic strain gauges. Finger BF in the heated hand was significantly lower than that in the control hand at TwS of 37 degrees -41 degrees C, mostly for the first few minutes of each heating period. Thereafter, finger BF in the heated hand gradually returned toward the previous values. At TwS of 39 degrees -40 degrees C, however, finger BF in the heated hand remained lower than the control values for the entire period of heating. At TwS of 42 degrees -43 degrees C, finger BF in the heated hand greatly increased after an initial transitory fall. In the forearm skin, however, no such vasoconstriction in response to local heating was observed. All this suggests that a rise in skin temperature to above the core temperature produces paradoxical vasoconstriction in the finger, which may be a mechanism to reduce heat gain through the hand heated locally at higher temperatures.

Adult↗

PubMed2006

Asymmetry of interhemispheric interaction in left-handed subjects.

In right-handed subjects the execution of a simple finger-tapping task is associated with an asymmetry of interhemispheric interaction, probably suggesting that the dominant left hemisphere inhibits the right one. The present study investigated the left-handed subjects in order to elucidate whether this asymmetry is related to handedness. Nineteen healthy subjects performed unimanual left, right, and bimanual auditorily paced finger-tapping tasks while neuromagnetic activity was recorded with a 122-channel whole-head neuromagnetometer (MEG). Simultaneously, we recorded activity of the first dorsal interosseus (FDI) muscle of both hands. By using the analysis tool dynamic imaging of coherent sources (DICS), oscillatory activity at alpha as well as at beta frequency within the primary sensorimotor (S1/M1) and premotor (PMC) cortex was localized. As expected, we observed oscillatory coupling between S1/M1 and PMC contralateral to the moving hand. Furthermore, coupling between left PMC and bilateral S1/M1 occurred in each movement condition, suggesting that the left PMC modulates neural activity in bilateral primary sensorimotor cortices independent of the moving hand. Coupling between bilateral S1/M1 occurred more frequently and significantly stronger during the right hand condition. This result demonstrates the same interhemispheric coupling pattern as in right-handed subjects, suggesting that the asymmetry of this interaction is not due to hand dominance. A specialization of the left premotor cortex either for superior motor control per se or for the execution of sequential tasks might account for these results.

Adult↗

PubMed2000

Comparison of second lumbrical and interosseus latencies with standard measures of median nerve function across the carpal tunnel: a prospective study of 450 hands.

The second lumbrical-interosseus distal motor latency (2LI-DML) was compared prospectively in 450 hands. Median nerve function was assessed by standard motor and sensory electrophysiological tests. In a control group of 100 hands the upper limit of normal for the 2LI-DML was 0.5 ms. In all hands studied the correlation coefficients of 2LI-DML were higher with sensory nerve tests than with motor studies. Carpal tunnel syndrome (CTS) was diagnosed clinically in 276 hands, and 174 showed no clinical signs of CTS. The 2LI-DML was prolonged in 269 of the 276 hands, with clinical signs of CTS and normal in 170 of 174 non-CTS hands. Thus the 2LI-DML resulted in a sensitivity of 97.5%. On the other hand, combining the standard tests yielded a sensitivity of 98.5 %. In 31 of 36 additional hands a lumbrical response was recorded, although motor and sensory responses form standard median nerve conduction studies were absent, and the 2LI-DML was substantially prolonged. The 2LI-DML therefore represents a highly sensitive, fast, easy-to-perform, and cost-efficient method to study median nerve function across the wrist and may help to localize the lesion in cases in which standard electrophysiological methods fail.

Adolescent↗

PubMed2006

Laparoscopic vs. hand-assisted laparoscopic sigmoidectomy for diverticulitis.

INTRODUCTION: Sigmoid colectomy for diverticulitis can be technically challenging because of severe inflammation in the left-lower quadrant and pelvis. We hypothesized that hand-assisted laparoscopic technique may facilitate laparoscopic completion of this surgery while retaining the short-term benefits associated with "pure" laparoscopic surgery, in which an incision is made only for extracting the specimen. This study was designed to compare the outcomes of patients who underwent totally laparoscopic or hand-assisted laparoscopic sigmoidectomy for diverticulitis. METHODS: We reviewed our prospectively collected patient database from July 2001 to June 2004 and compared the intraoperative data and postoperative outcomes of patients who underwent elective laparoscopic or hand-assisted laparoscopic sigmoidectomies for diverticulitis. Complicated patients (with abscess or fistulas) also were separately analyzed. RESULTS: The hand-assisted laparoscopic (mode age, 57 years; 48 percent male) and laparoscopic sigmoidectomy (mode age, 56 years; 90 percent male) groups were similar with regard to age and gender. Overall, patients who underwent laparoscopic (n = 21) vs. hand-assisted laparoscopic (n = 21) sigmoidectomies had a significantly longer operative time (197 +/- 42 vs. 171 +/- 34 minutes, P = 0.04) and shorter incision length (5 +/- 2.1 vs. 9.3 +/- 4.1 cm, P = 0.0001). Patients with complicated diverticulitis (n = 14; abscess, colovesical fistula, enterocolic fistula) who underwent laparoscopic sigmoidectomies (n=4) had a significantly longer operative time compared with hand-assisted laparoscopic sigmoidectomy (n = 10) group (255 +/- 18 vs. 177 +/- 34 minutes, P = 0.001). Conversion rate for the laparoscopic group was significantly higher (3/4 vs. 1/10, P = 0.04, Fisher exact) when complicated diverticulitis was present. There were no differences in postoperative outcomes or incision lengths in the complicated group. CONCLUSIONS: Outcomes after hand-assisted laparoscopic sigmoidectomy for diverticulitis are similar to those seen in the pure laparoscopic method, with lower conversion rates and shorter operative times. Hand-assisted laparoscopic sigmoid resection for diverticulitis is an attractive alternative to a "pure" laparoscopic method in complicated cases.

Adult↗

PubMed2007

Hand-assisted laparoscopic radical cystoprostatectomy and urethrectomy with ileal conduit construction.

INTRODUCTION: Hand-assisted laparoscopy was first performed in the 1990s by inserting the surgeon's finger or hand through a small tight wound. Although leakage of gas from the incision initially limited the usefulness of the technique, the hand-assisted procedures have advanced extensively since the introduction of the hand-assisted laparoscopy port. Laparoscopic procedure has only rarely been applied to radical cystoprostatectomy. Favorable reports for laparoscopic radical prostatectomy encouraged us to attempt a cystoprostatectomy under hand-assisted laparoscopy. PATIENT: The patient was a 70-year-old male with an invasive bladder tumor and no distant metastasis. Informed consent for undergoing hand-assisted laparoscopic radical cystoprostatectomy and ileal conduit construction was obtained. METHODS AND RESULTS: The bladder was dissected free and extracted whole through the incision for the hand port. The bilateral ureters and a loop of small intestine were withdrawn through the same incision. An ileal segment was isolated and small intestine continuity was recovered. Each ureter was anastomosed to one extreme of the ileal segment that was then reintroduced into the abdomen. The stoma was constructed through the right side port without additional incision. No intraoperative complications were observed. Recuperation was unusually quick and painless, and few postoperative analgesics were needed. CONCLUSIONS: Hand-assisted laparoscopic cystoprostatectomy and urinary diversion could provide the advantage of decreased postoperative morbidity without the long operation time and technical difficulty of a strictly laparoscopic procedure.

Aged↗

PubMed1989

Energy of stabilization of the right-handed beta alpha beta crossover in proteins.

An explanation in terms of conformational energies is provided for the observed nearly exclusive preference of the beta alpha beta structure for forming a right-handed, rather than a left-handed, crossover connection. Conformational energy computations have been carried out on a model beta alpha beta structure, consisting of two six-residue Val beta-strands and of a 12-residue Ala alpha-helix, connected by two flexible four-residue Ala links to the strands. The energy of the most favorable right-handed crossover is 15.51 kcal/mol lower than that of the corresponding left-handed cross-over. The right-handed crossover is a strain-free structure. Its energy of stabilization arises largely from the interactions of the two beta-strands with one another and with the alpha-helix. On the other hand, the left-handed crossover is either disrupted after energy minimization or it remains conformationally strained, as indicated by an energetically unfavorable left twisting of the beta-sheet and by the presence of high-energy local residue conformations. In the energetically most favorable right-handed crossover, the right twisting of the beta-sheet and its manner of interacting with the alpha-helix are identical with those computed earlier for isolated beta-sheets and for packed alpha/beta structures. This result supports a proposed principle that it is possible to account for the main features of frequently occurring structural arrangements in globular proteins in terms of the properties of their component structural elements.

Energy Metabolism↗

PubMed1984

Clinical differences between typical and atypical cleft hand.

To clarify the clinical features of the cleft hand and to differentiate the typical cleft hand from the atypical, hand pattern profiles were used. In cases of typical cleft hand, the metacarpal or the proximal phalanx on either side of the cleft are longer than on the unaffected side. Conversely, in cases of atypical cleft hand, the hand pattern profile shows a dysplastic bone formation. There was an obvious difference in the metacarpal pattern between typical cleft hand and failure of formation. The metacarpal pattern of typical cleft hand is like that in webbing of normal fingers, and the metacarpal pattern of failure of formation is like the pattern in symbrachydactyly.

Diagnosis, Differential↗

PubMed1989

Asymmetrical transfer of training between hands: implications for interhemispheric communication in normal brain.

Two experiments are presented which investigated claims of asymmetrical transfer of training between the hands/hemispheres. In Experiment 1, 96 right- and left-handed male undergraduates practiced an inverted-reversed printing task with either the right or the left hand. Transfer to the opposite hand was then compared to same-hand transfer, in a between-subject design. In Experiment 2, 176 right-handed boys and girls were tested at ages 7, 9, and 11 years. For right-handed subjects in both experiments, the left hand benefited more from opposite-hand training than did the right. The reverse was true for left-handers in Experiment 1, although one group (who wrote with the "inverted" position) showed little transfer in either direction. Two current models of interhemispheric interaction do not satisfactorily explain these findings. A third model, based on cross-activation, may provide a more effective alternative.

Adult↗

PubMed2006

Metaphor explanation attenuates the right-hand preference for depictive co-speech gestures that imitate actions.

Differential activation levels of the two hemispheres due to hemispheric specialization for various linguistic processes might determine hand choice for co-speech gestures. To test this hypothesis, we compared hand choices for gesturing in 20 healthy right-handed participants during explanation of metaphorical vs. non-metaphorical meanings, on the assumption that metaphor explanation enhances the right hemisphere contribution to speech production. Hand choices were analyzed separately for: depictive gestures that imitate action ("character viewpoint gestures," [McNeill, D. (1992). Hand and mind. What gestures reveal about thought. Chicago: University of Chicago Press.]), depictive gestures that express motion, relative locations, and shape ("observer viewpoint gestures"), and "abstract deictic gestures." It was found that the right-hand over left-hand preference was significantly weaker in the metaphor condition than in the non-metaphor conditions for depictive gestures that imitated action. Findings suggest that the activation of the right hemisphere in the metaphor condition reduces the likelihood of left hemisphere generation of gestures that imitate action, thus attenuating the right-hand preference.

Adult↗